THE SHADES IN RICHARD TWOHIG'S GARDEN APARTMENT ARE DRAWN TIGHT AGAINST THE SUMMER SUN. This is partly because it's 94 degrees in Knoxville, Tenn., this afternoon, but also because light can trigger one of his bad headaches, the kind that make his knees buckle. His kids have grown accustomed to dimmed surroundings.

They've been cavorting on the living room carpet, Lizzie with her fuzzy pink dog named Princess, her little brother, Damon, with his prized jeep. Their chirpy ebullience isn't unusual for a 6-year-old and a 3-year-old who haven't had much chance to romp outside today but noise can bring on Twohig's migraines, as well. "Why don't you go up and play a while?" he suggests mildly, and they troop upstairs to their shared bedroom.

The apartment, which the family moved into three weeks ago after a nomadic year, still feels a bit empty. There's a couch and a coffee table and a big TV in the living room, but the walls are bare. Twohig wishes he had a yard for the children and their real dog, a boisterous Great Pyrenees named Athena. Still, the place is clean and comfortable, and he can manage the $570 rent on the disability checks that the Department of Veterans Affairs sends each month.

"If I have a good day, I try to take them up to the park at the school," he says, knowing that the kids should probably be outdoors more. It's only a two-minute drive. But he doesn't have so many good days.

Since he was thrown from a moving armored vehicle in Baghdad in May 2003, and landed on his head, the former Army corporal says he has suffered from near-constant headaches. This afternoon's is the easier kind to take: He figures the throbbing registers a 6 or 7 on the 10-point scale that injured vets learn to use to quantify their pain. The more severe headaches come perhaps once a week now, he says, and even the heavy-duty drugs he takes can't really blunt them: "Before, I would pass out in the shower, things like that. You kind of learn when they're coming on. So when I feel lightheaded and my legs get weak, I crouch down" so he doesn't fall. Those are the sort he rates a 10.

The headaches are one of the disabling conditions Twohig incurred in the line of duty, the Army acknowledges, along with a "mood disorder with depressive features." He appears fit, in his patched jeans and T-shirt: 6-foot-2 and, now that the bloat from earlier drug regimens has dissipated, 180 pounds. Tattooed snakes and samurai, souvenirs of Fort Bragg, twine up his arms. With his blue eyes, cleft chin and crew cut, Twohig looks like the same paratrooper -- Bravo Company, 1st Battalion, 325th Airborne Infantry Regiment, 82nd Airborne Division -- who easily handled 25-mile marches wearing a 35-pound pack and carrying an M4 rifle.

But he isn't. He often forgets what his mother, retired Marine Corps Maj. Belinda Twohig, tells him on the phone moments after she has said it. He's lethargic; he can't concentrate. If he has to enter a mall, he calculates which entrance will let him come and go with the least amount of human contact. A guy who used to happily devour an entire sausage pizza and some cheese sticks for dinner, he now has scant appetite and, troubled by nightmares, sleeps perhaps three hours a night.

He can't imagine holding a job in this condition. "What can I actually do?" he asks. "Physical work gives me migraines. I vomit all the time . . . I'm on morphine; I'm addicted. I'm just a mess."

Ask him his age, and he takes a long, thoughtful pause before replying. "Twenty-five."

Despite the migraines, the tinnitus (ringing in his ears), the chronic shoulder dislocation and other documented physical problems, he works hard at caring for the children, doing their laundry, cooking them simple meals, supervising them with great patience. (Their mother, from whom he is separated, serves with the Navy in Virginia.)

"Damon, either sit up in your chair or go upstairs and play," he cautions calmly, when the kids grow restive watching the Cartoon Network. "Do not sit on your sister." He rarely raises his voice.

In fact, Twohig's response to most things is muted. He doesn't laugh much, doesn't seem to take much pleasure in Lizzie and Damon's exuberant antics. It might be the meds or the pain or the prospect of a life in which he may never work, but there's a flatness to his personality that his family finds new and troubling.

One subject prompts a more animated response, though, rousing him to noticeable anger: the U.S. Army.

Like any member of the armed forces injured in the line of duty and no longer able to serve, Twohig has been grappling with a complicated disability system that determines whether he merits military retirement. Thousands of other soldiers, sailors, airmen and Marines are dealing with the same process. With U.S. troops still in Afghanistan and the war in Iraq entering its fourth year, the annual caseload of troops injured severely enough to be considered for retirement has climbed nearly 53 percent since 2001, to about 23,000 a year. The great majority don't get it, which has made the disability system the object of confusion, apprehension and suspicion among injured veterans and their advocates.

In Twohig's case, an Army Physical Evaluation Board ruled in 2005 that he wasn't disabled enough to qualify, a decision that deprived his wife and children of health insurance through him. He and his family have been battling the finding since.

To Twohig, the fight is based not only on finances but also on principles. He enlisted; he trained; he followed every order "to a T," he says. He paid the price, and now it feels as though the Army is abandoning him.

"I have a son, and I wouldn't let him join the Army," Twohig announces, agitated. "They don't really care about soldiers. They got their mission, and if you're hurt, oh, well."

His voice tightens: "After we're no good to them, they just get rid of us."

RICHARD TWOHIG REMEMBERS LITTLE ABOUT HIS TIME IN IRAQ. His commanding officer, Capt. (now Maj.) Jeffrey Burgoyne, says that Bravo Company saw "a lot of firefights" in Fallujah and other towns as it made its way to Baghdad in late April 2003. But what Twohig can summon up from Iraq aren't battles but the heat and the odd quality of the sand ("it had been cooked so long that when you stepped on it, it broke into pieces") and the occasional K rations, "in big old metal things they heated up," that tasted better than meals-ready-to-eat.

Nor is much recorded about the accident that damaged Twohig -- not even the exact date it occurred. The Commander's Performance Statement, signed by Burgoyne, says Twohig was "on combat patrol" aboard a Bradley armored fighting vehicle, "going approximately 45 mph when it turned a corner in downtown Baghdad, causing Cpl. Twohig to be thrown from the vehicle. He fell on his head and lost consciousness."

Burgoyne now says that the vehicle wasn't a Bradley but a smaller, older M113 about to leave the unit's walled compound and thus going far more slowly. But Burgoyne was at a forward operating base five miles away and only heard of the accident by radio. In any event, "the guy fell off a moving truck; that's significant." And when the battalion learned that Twohig was being helicoptered to Germany, Burgoyne says, "that's when we realized it was more serious than we thought."

A neurology consultation at the Army hospital in Landstuhl, dated May 20, 2003, is the first record of Twohig's injuries, noting his head trauma, throbbing headaches and other symptoms, including memory loss. "I didn't remember my Social Security number or my unit or people I worked with," he says. He even, temporarily, forgot that his son had been born a few months earlier.

He was flown back to Fort Bragg a couple of weeks later. As he made the rounds of doctors at Womack Army Medical Center, Twohig says, his memory improved somewhat, but the headaches and psychiatric symptoms persisted. Belinda Twohig felt her hopes for a speedy recovery sink. She accompanied her son to a neurology appointment in which the doctor told them that when Richard's migraines struck, he should just take his meds and lie down in a quiet, dark room; there was no purpose in going to the emergency room, because nothing else could be done, no stronger medication prescribed. The prognosis was uncertain. After a concussion, the brain needs time to heal, the neurologist cautioned; it could take a year or two to see any improvement.

Meanwhile, Twohig's marriage was fraying under the strain. He says he was vomiting frequently, sleeping a lot and feeling depressed. He could no longer mow the lawn or help with errands; the house, despite his two young children, had to remain quiet. "It just changed the relationship," Twohig says. "She didn't understand and want to deal with my problems." His wife, Sang, did not respond to phone calls seeking comment. At times, he felt so lousy that he wouldn't even come to the phone when his mother called. "We had a close relationship; he always talked to me," Belinda says. "So the withdrawal was the first thing I noticed." When they did talk, she was aware of "confusion. I'd ask him something -- 'How was your day? Have you taken your meds?' 'Yeah, I think so' . . . Just a slow, lethargic answer. And this is not Richard."

Frightened as she was, she told herself that at least the Army would, in her words, "take care of him" and his family. After more than two decades in the service, she knew the outlines of the disability system, and she assumed he would be able to retire. For her son, though, this was uncharted territory.

The magic number, he quickly learned, is 30 percent -- the point at which a disability is considered to be severe enough to prevent someone from functioning normally in the workplace. Those with 30 percent or higher disability ratings can retire with benefits that include monthly checks for the rest of their lives, access to commissaries and post exchanges on military bases, travel on military aircraft and, most coveted, coverage by TriCare, the military's health insurance plan, for themselves and their dependents, present and future. Those rated below 30 percent usually receive a severance check from the military: two months' pay for each year's service, up to 12 years. They can then apply for benefits from Veterans Affairs, which also rates disabilities and provides monthly checks but doesn't offer the other advantages of retirement.

The practice of compensating injured soldiers dates to Colonial times, but the current system has its roots in World Wars I and II. Congress mandated the development of ratings for disabilities in 1917; the Career Compensation Act of 1949 then linked the amount of payments to the degree of disability, establishing the 30 percent threshold. "The thinking was, those rated less wouldn't be so handicapped as to warrant long-term disability pay," explains Rick Surratt, deputy legislative director of Disabled American Veterans. "A lump sum would hold them until they could get reestablished in the workplace."

Getting any rating at all can take many months, however. Once an injured service member is medically stable, he must wait for a military doctor to write a narrative summary of his condition. Then a board of physicians reviews the medical records -- often thick with test results, multiple diagnoses, lists of medications and addenda -- to decide whether he meets retention standards. If not, an informal Physical Evaluation Board assesses the severity of each disability that makes a service member unfit for duty and assigns it a numerical rating, based on detailed guidelines in the Veterans Affairs Schedule for Rating Disabilities.

"What we're attempting to do is approximate the average loss of earnings capacity," says Tom Pamperin, who oversees revisions to VA's guidelines, a nearly unceasing project. Amputation at the upper third of the thigh, for instance, merits an 80 percent disability rating. Amputation at the middle or lower third of the thigh: 60 percent. Mental disorder characterized by "occupational and social impairment, with deficiencies in most areas, such as work, school, family relations, judgment, thinking or mood . . .": 70 percent. Migraines "with characteristic prostrating attacks occurring on an average once a month over the last several months": 30 percent.

Twohig picked up the gist of the process at the Fort Bragg gym, where he worked with other soldiers too disabled for regular duty. He checked ID cards and handed out towels four hours a day -- and says he found even that difficult, because the clanging of free weights and the thunking of basketballs brought on migraines. Meanwhile, he and his buddies pondered the mysteries of disability retirement. There was ample time to compare notes; the pace at which cases proceed can be exasperatingly slow, in violation of the Pentagon's own guidelines.

Twohig waited 17 months to receive the medical evaluation board report that found him no longer fit to serve. Meanwhile, he watched as others received ratings too low to qualify for retirement. One guy with what Twohig describes as "titanium vertebrae" got a 10 percent rating. Another received no severance.

In fact, the majority of injured soldiers fall short of the magic number; the informal evaluation board rates them below 30 percent. The Defense Department reports that the Army, which handles more than half of the military's disability cases, put less than 4 percent of the 10,460 active duty soldiers and reservists it evaluated last year on the permanent disability retirement list and less than 15 percent on the temporary list. (Temporary retirees undergo periodic reassessments of their condition for as much as five years before a final decision.) By comparison, the Navy (including the Marine Corps) retired about 35 percent of its injured, temporarily or permanently, and the Air Force about 24 percent, the Defense Department says.

The difference, the Army's disability agency says, may reflect a higher proportion of musculoskeletal injuries that can interfere with soldiers' duties but have "mild" impact on civilian employability, resulting in severance pay rather than retirement. The Army also has "a unique policy" of not granting retirement for pain that has "no clear cause or objective findings." But, the agency concedes, "it is not possible to state with certainty what might account for the difference" between the Army's and the other branches' retirement rates.

At Fort Bragg, soldiers sometimes find it hard to understand why some people qualified for disability retirement and others didn't. "You don't really know too much about it until you start doing it," says Twohig's friend Jacob Biehn, a former specialist who suffered multiple gunshot wounds in Iraq and eventually received a 30 percent disability rating -- which allowed him to retire but struck his comrades as minimal, given his injuries. "When you go to find out what they decided," he says, "it could be a good day or a bad day."

For Twohig, it was a bad day. He called his mother from Fort Bragg on Nov. 2, 2004, sounding "shaken up," she recalls. "He said: 'Mom, it came back 20 percent . . . How am I going to survive? How can I take care of my family?' I said, 'Son, calm down. We're going to fight this.'"

TWOHIG HAD THE RIGHT TO CONTEST HIS DISABILITY RATING BEFORE A FORMAL PHYSICAL EVALUATION BOARD, and his mother stood ready to help him. A lifelong Marine and a congenital optimist, Belinda felt more determined than discouraged, convinced that the system had erred and would correct itself.

Each branch of the military provides opportunities for injured service members to challenge their ratings, but most of the injured simply pocket their severance checks and go home. Only 20 percent of soldiers ask for a formal hearing, at which an attorney can present evidence and call witnesses, the Army says. Then only half of those soldiers proceed with the hearing.

Perhaps that indicates most injured soldiers are satisfied with their ratings. But veterans groups say that more wounded service members would challenge their ratings if it weren't so complicated and time-consuming.

"It's probably one of the most convoluted workman's compensation systems in the world," says Steve Robinson, government affairs director at Veterans for America.

Most of those hurt in the line of duty are young, weary of fighting and anxious to return to their civilian lives, Robinson and others point out. A severance check for $10,000 or $12,000 (the latter was Twohig's severance after 49 months of service) can seem to be a lot of money. If a case has already dragged on for months, seeking a formal hearing -- even if that's in a service member's best interest -- can require still more time and frustration.

All of which tends to discourage the injured from taking on the system -- and some veterans advocates suspect that the Pentagon, openly worried about ballooning health-care costs, prefers it that way. Medical benefits are not discretionary; the Defense Department must pay the tab. "Increasingly, it's having a direct impact on the department's ability to meet its needs for equipment, replacement equipment, personnel," says William Winkenwerder, assistant secretary of defense for health affairs. "The costs of retirees, the health-care costs, are a great concern to us."

Nevertheless, the Defense Department says that each disability case "is evaluated on the basis of relevant clinical information," and the Army vehemently denies that its evaluation boards award lower ratings because of pressure, direct or indirect, to hold down costs.

"No one has discussed that financial burden with me at all," says Col. Carlton Buchanan, the new deputy commander of the Army's Physical Disability Agency, which oversees its evaluation system. "Nobody has said I have a particular requirement or a goal or a quota or a threshold that I can't surpass . . . I feel no pressure whatsoever to set limits on disability. We will do what's right."

Still, civilian attorneys who argue military disability cases see a pattern in the ratings.

"The informal board will tend to lowball," says Vaughan Taylor, who practices in Jacksonville, N.C., and has argued dozens of disability cases. Like many of the small fraternity of civilian lawyers who specialize in military cases, he is a former military lawyer, or judge advocate, himself. "It's almost as if the informal board exists to give out the standard 10 percent, and then see who squawks."

"The unwritten guidance seems to be: Push these people over to the VA, and let them pay for this," agrees Joseph W. Kastl, a former Air Force lawyer who now calls his Bethesda firm the Military Defender.

Sometimes, service members find the system works well for them. One of Taylor's clients, former Marine Sgt. Eric LeClair of Swansboro, N.C., was unhurt during the first wave of the Iraq invasion, only to take a bad landing during a martial arts test aboard the USS Iwo Jima in September 2003. His list of injuries was pages long: a traumatic brain injury, nerve palsy, bone spurs and degenerated discs. "I can't lift a half-gallon of milk above my waist, and it's been like that for two years," LeClair said this past summer.

The night before he was scheduled to learn his disability rating, he and his wife were too jittery to sleep. They had seen other seriously injured Marines "going through it and getting the shaft," in LeClair's opinion. Despite the pages of additional material and independent physicians' findings that his lawyer had amassed, LeClair expected the same result. But the next morning, to his surprise and his wife's enormous relief, he was placed on the temporary retirement list with a 60 percent rating -- no formal hearing needed.

Former Master Sgt. John Alden Millan of Newland, N.C., had to go a step further. An MP with the Army National Guard, he injured his neck jumping from a truck the day his unit arrived in Iraq. Despite surgery, he says, he still suffers from back pain and severe headaches. When he received a disability rating of 20 percent, he and his attorney, Jack Gately, asked for a formal evaluation board hearing. After Gately presented testimony and Millan answered questions, the board told Millan that his injuries warranted a 40 percent rating. "I said, 'I concur, sir,' signed my paperwork and left," Millan says.

But formal boards reject cases, too. Former Maj. Lionel Walton, who lives in Prince George's County, already had a 20 percent disability from past injuries but had chosen to remain in the Army Reserves ("I bleed green," he says), eventually serving 24 years. In Iraq, he says, he hurt his knee jumping from a truck and running from rockets and car bombs, and injured his back loading heavy cases. Now, at 46, "I can't walk 30 yards without having to sit down; I'm at level 8 pain every day," Walton says. He also struggles with post-traumatic stress disorder.

When his informal evaluation board found him 20 percent disabled -- the same rating he'd had before Iraq -- Walton hired Kastl. In September, the formal evaluation board at Walter Reed Army Medical Center declined to raise his rating. He was stunned: "My government, my country, should do better by me."

Refusing to back down, Walton appealed the formal board's decision to the Physical Disability Agency, and enlisted the help of Maryland Senator Barbara Mikulski's office. He's convinced that her involvement eventually helped raise his rating to 60 percent, and that infuriates him. "It's a shame," he says. "I fought to the end, but a lot of soldiers have given up because of this nonsense."

NORMALLY, THE TWOHIGS AREN'T THE SORT OF PEOPLE INCLINED TO TAKE ON THE MILITARY. Both Richard Twohig's parents were career Marines; his younger brother, Chris, has enlisted in the Marines and shipped off to Parris Island. This is a family that believes every young person should serve this country.

Belinda Twohig trusted so fully in the military's commitment to caring for its own that the idea of looking beyond an Army attorney to represent Richard didn't initially cross her mind. But when she called a friend who was a judge advocate, he warned, "Belinda, you don't fight the Army with the Army." What she needed, he said, was a civilian lawyer specializing in military cases. After a little research, he sent her a name: Mark Waple, a West Point graduate and former judge advocate who practices in Fayetteville, N.C.

Waple has argued perhaps 200 physical evaluation board cases, going back to the Vietnam War era. For most of that time, he says, the evaluation boards "tried very hard to be as fair as possible." Now he describes the system as "broken."

Wounded service members are supposed to be guided through the confusing thicket of disability regulations by physical evaluation board liaison officers, universally known as PEBLOs, whose job is to explain the process, advise service members of their rights and assemble their files. But service members complain that documents get lost, that files are incomplete; some report that the liaisons discourage appeals and the use of outside attorneys.

"Sometimes I feel half of what I do is explain what a PEBLO should have already explained," says Danny Soto, a national service officer for Disabled American Veterans, the only vets organization permitted an office at Walter Reed.

Liaison officers handle many cases; in the Army, for example, they counsel an average of 15 to 30 people a day, not including phone calls. Twohig only remembers meeting his liaison officer once: the day she told him he wouldn't be retired.

The Army has tried to keep up with the sharp rise in disability cases, expanding the Physical Disability Agency staff by 50 percent since 2003, and adding 40 percent more liaison officers and assistants. The Army's caseload, however, has soared by more than 80 percent since 2001.

At Walter Reed, where two part-time Army lawyers handled disability cases in 2003, three lawyers and a paralegal now work full time presenting cases to the formal evaluation board. These lawyers get high marks from their civilian counterparts and from vets groups for knowledge and competence, but low grades on having enough time to put together strong cases, which can involve preparing witnesses and gathering further medical documentation. Each lawyer at Walter Reed handles an average of 256 cases each year, and often doesn't meet a client until the day before the evaluation board hearing, when the attorney spends an hour or so preparing the soldier to testify.

"I don't know how you can prepare adequately for a hearing, a full and fair hearing, if you pick up the case file the day before, two days before," says civilian lawyer David Sheldon, who has a military practice in the District.

The Army disagrees. "Lengthy e-mail messages and in-depth phone calls from the paralegal and the attorney ensure that adequate contact is made in sufficient time before the hearing," says Lt. Col. Samuel Smith, Walter Reed's supervising staff judge advocate, via e-mail because the Army barred in-person interviews with any legal staff or with evaluation board members.

Few of the injured hire their own attorneys to contest findings, even though they have that right. A key barrier is money: A civilian lawyer specializing in military cases will likely charge $5,000 or more to prepare for a formal hearing, with no guarantee of success.

Waple was blunt about that when the Twohigs went to see him in early 2005. He thought Richard was clearly entitled to retirement. But migraines are hard to get rated for, because sufferers can rarely document how frequently they occur, something the physical evaluation board wants to know. Richard would have been better served, Waple said, if his neurologist had told him to go to the emergency room whenever he had an incapacitating headache, or even advised that he keep a diary. Waple, however, could call a witness -- Belinda -- who could explain why there was no record of how often Richard's headaches struck.

Richard's psychological symptoms presented a different problem. Waple knew the board might not give much credence to his mood disorder.

The way the military rates psychiatric injuries -- or doesn't -- is a sore subject among veterans groups and civilian lawyers who handle disability cases. The incidence of mental health problems among those returning from Iraq appears high. An Army research team, reviewing the records of more than 300,000 soldiers and Marines, reported last year that more than one-third of Iraq veterans had visited mental health clinics at least once in their first year at home; they were considerably more likely to show signs of psychological distress than those who had served in other overseas locations such as Afghanistan or Bosnia. Yet critics charge that evaluators are particularly skeptical about diagnoses of post-traumatic stress disorder and other psychological injuries.

"If they've been shot five times and need multiple surgeries, and it's very obvious to the doctors what's wrong, then it's a lot easier," says Charlotte Cluverius, a Washington attorney who represents service members at disability hearings. "The burden on the service member is much, much higher with psychological issues, even though those can be just as devastating and incapacitating."

Danny Soto agrees. At Walter Reed, where he counsels dozens of soldiers each week, he thinks that just 40 to 50 percent are being rated correctly for their injuries. When it comes to clear-cut physical problems, something as visible and inarguable as amputation, "they get that right," Soto says. "If you're talking traumatic brain injuries, psychiatric injuries, it drags on."

The Army rejects the notion that large numbers of injured soldiers aren't being rated correctly. Its Physical Disability Agency reviews 25 to 30 percent of informal and formal evaluation board decisions, and is satisfied with its work.

David Armitage, the agency's senior medical adviser, acknowledges that correctly evaluating post-traumatic stress syndrome and other mental disorders -- or any self-reported disability -- can be difficult. "It's a fact-finding matter," he says. "We look for supportive evidence." Otherwise, a condition such as migraine headaches "is too easily conjured up or exaggerated." But he adds, "that's true throughout the entire disability world, not just in the military . . . I think we're doing better every day."

Waple wasn't so sanguine. He told the Twohigs that he wasn't having much success with the Army and that the odds weren't high that the formal evaluation board would raise Richard's rating to 30 percent. Besides, Waple's services, including the fee for the independent forensic psychologist's evaluation he recommended, would cost about $6,000. Belinda, who had just paid lawyers' fees to divorce Richard's father, blanched. But they agreed to proceed, with each parent paying half the cost.

Richard's case would be heard at Walter Reed, where the evaluation board scheduled the hearing for a day when Waple had a court appearance elsewhere and then refused to grant a five-day delay. That meant Waple would prepare Twohig's case but that an Army lawyer would have to present it.

Still, the Twohigs felt hopeful. Once the board heard the full story, Belinda was sure, "they are going to realize that there was wrong done. They're going to see and say, 'Okay, Richard should be 30 percent.'"

BELINDA ACCOMPANIED RICHARD TO WASHINGTON FOR HIS HEARING IN MARCH 2005. For one thing, he was in no condition to drive, she says, "from the stress and all the meds he was on." In addition to the pain drug Dilaudid, he was taking medications for his migraines, for nausea and sleeplessness, and for depression. Belinda would also be a witness, able to testify about the changes in her son and about what his neurologist had advised.

It was a stressful time. Belinda, who had been teaching ROTC at Florida A&M University, was newly divorced and about to retire from the Marines after 28 years, forgoing an expected promotion to lieutenant colonel. She planned to sell her house in Tallahassee and look for a job in Tennessee, where she would be near Richard and her grandchildren.

"My children have sacrificed a lot for my career," Belinda says. "There were deployments; there were a lot of long hours." She can still tick off her absences: the 10 weeks her two boys stayed with her sister while she was at Officer Candidates School, the six months' further training at Quantico when she got home every other weekend, a stint at Guantanamo . . . "I wasn't always there for them, I feel."

Now, she intended to be. So while Richard lay in the back seat of her '94 Mustang, she drove north, stopping at a highway rest area when a headache nauseated him and he needed to vomit.

This wasn't the son she had raised. Growing up mostly in Jacksonville, N.C., he was the kind of kid who was happiest outdoors, a deer and duck hunter, a year-round surfer at nearby beaches, a halfback on a traveling soccer team. "Richard always had friends; Richard used to joke a lot," she remembers. She wasn't pleased, when she and her husband went off one weekend, to learn that Richard had invited his soccer buddies over for a beer bash that drew the police. But the incident does remind her that back then, "he liked to be around people. He was always dragging someone home."

He went off to North Carolina A&T to study business management, and, toward the end of freshman year, met a young woman in a club. He and Sang, the daughter of Cambodian immigrants, went out for a while, had Lizzie when they were both 19, then married. Twohig left school and took jobs flushing radiators at Jiffy Lube and loading United Parcel Service trucks, but he had trouble earning enough for a family, and none of his employers supplied benefits. The military would. It might be "the best option to get my degree and help the family," he thought. "My mom did it that way, went in the Marine Corps, got her education. So did my dad." And the Army was offering $20,000 signing bonuses. He walked into the recruiting station in Jacksonville and enlisted in early 2001. When he graduated from boot camp, his mother swore him in, an officer's prerogative and an act she now sometimes regrets.

Twohig was sure after September 11 that he'd be sent to Afghanistan. But his unit remained at Fort Bragg until Iraq, a war whose political dimensions he gave little thought to. "I looked on it more as a job," he explains. "You're supposed to do it. Your feelings don't really matter."

He had been a good soldier, his mother thought, and he was a good man. She had faith, and not solely in the military.

In the months since his accident, Belinda, a churchgoing Catholic, prayed the rosary as she walked around the track at Florida A&M each morning. She was praying again as they rounded the Beltway and headed for a hotel in Silver Spring.

THAT AFTERNOON, THE TWOHIGS MET WITH ASSIGNED MILITARY COUNSEL DAVID WHITE, who, using Mark Waple's brief and materials, would represent Richard at the hearing next day. White explained the procedure and, as Belinda remembers it, said Richard stood a decent chance of having his 20 percent rating raised.

Richard hardly slept that night. When they reported to Building 7 at Walter Reed the next morning, both in uniform, he felt ill and vomited a little in a hallway water fountain; Belinda fished some tissues from her briefcase and cleaned up the mess. To ward off an approaching migraine, he took his anti-nausea pills and Dilaudid, which tended to undermine his already-diminished ability to concentrate. "He looked like a zombie," his mother says.

The Physical Evaluation Board at Walter Reed is one of three meeting around the country for the Army; the others are at Fort Lewis in Washington state and Fort Sam Houston in Texas, sometimes supplemented by a mobile board. (The Navy and Air Force have their own physical evaluation boards.) A typical board has three members, one of whom is a physician. But that doesn't mean anyone on the board has had previous experience in evaluating disabilities; the physician hearing about brain injuries could be a dermatologist or an obstetrician. Members of the Army board take a five-day classroom course before they start adjudicating cases; the rest of their training comes on the job.

Inadequate training is among the problems that investigators have repeatedly cited in calling for improvements to the disability system. For nearly two decades, studies by both military and civilian teams -- the Army Audit Agency, the Defense Department's Inspector General, the Rand Corp. -- have criticized the system's inconsistencies, its delays, its lack of oversight and quality control. The latest report, issued by the Government Accountability Office last year, sounded many of the same themes, and the Defense Department didn't disagree. The Pentagon says a number of improvement efforts are now underway, including the long-planned computerization of all health records.

The Army, however, insists that it is already doing a good job. Armitage, who helped develop the Army's five-day training course, defends the members of the evaluation boards and their preparation. "These are people who know what soldiering is all about; they know the stresses that soldiers undergo; they know what the requirements are for soldiers to perform," he says. "They've been there."

The evaluation board that met to consider Twohig's case included a longtime infantry officer as president (he has since retired), a retired Navy psychiatrist as the medical member and a personnel management officer who had served in Iraq. They met in Room 235, a small space hung with Army insignia and posters of the human spine. Each of the three members and the soldier had a microphone on the table before him so that the hearing could be recorded on a CD.

It's supposed to be a non-adversarial proceeding. Some soldiers find it intimidating, nonetheless. For Twohig, it mostly seemed perplexing. The transcript shows that several times, as the attorney had him describe his injuries or board members chimed in with questions, he sounded muddled, not quite able to grasp what was being asked.

Physical Evaluation Board president Col. James Babbitt (after Twohig testified that he had trouble concentrating): If the 1st Sergeant tells you, "Go to 1st Platoon and find the Platoon Sergeant and tell him I want to see him at 2 o'clock," can you do that?

Twohig: Yes.

Babbitt: If he says, "Go find the 1st Platoon Sergeant, tell him I want to see him at 2 o'clock, find the 1st Squad Leader and tell him I need to see him right now, and tell the 2nd Squad Leader I'll see him tomorrow," would you have any problem delivering those messages?

Twohig: What?

Belinda Twohig also testified, speaking at length about the changes she had seen in her son since his accident, his isolation and memory problems, his physical incapacity. "There is depression, because he feels he is incapable or cannot achieve any dreams that he had before," she said. "I think that the depression is coming because he doesn't know how to get better, and, you know, I don't either . . ."

But Babbitt prevented her from testifying about what the neurologist had said about not needing to seek further medical attention when the migraines hit. "We've brought that out already," he said. "That's not necessary. That's just duplicious."

After nearly two hours, the board recessed briefly. Then Babbitt read its decision: that Richard was physically unfit to perform his duties, that he had "post-concussive syndrome associated with headaches, dizziness, bilateral tinnitus, nausea, decreased concentration and forgetfulness" that "limit his activities of daily living." That he took "a narcotic substance, mood stabilizing and antidepressant medications." That he further had "mood disorder with depressive features manifest by chronic irritable mood, insomnia, decreased appetite, social withdrawal and low self-worth."

It sounded to the Twohigs as though the board saw things their way. Then Babbitt read Richard's rating: 10 percent.

After thanking Richard for his service, the board adjourned; the recording equipment was turned off.

Belinda Twohig remembers erupting in shock. "I don't believe this!"

"Mom, what happened? What are they saying?" Richard didn't understand.

"I gave the Army a perfectly capable young man, and what you give me is somebody incapable of working, and you tell me that's only worth 10 percent?" Belinda exclaimed.

The board president said he understood her distress.

"I don't believe we are not taking care of him," she said.

"That's what the VA is for," she remembers Babbitt saying.

One board member, Lt. Col. Nick Gnemi, disagreed with the finding and announced he would submit a minority report, a rare occurrence. As the Twohigs waited in the anteroom while Gnemi wrote it, Richard was anxiously wondering how he could take care of Sang and the kids. They would have to sell the house they had bought just two years earlier. "He was just ripping inside," Belinda says.

Sounding stronger than she felt, she told him not to worry, that they would get through this. She didn't want Richard to see her in tears, and she didn't want to show emotion before the other officers, "especially that president." So she found a corner downstairs, wept briefly, dried her face.

Gnemi handed them a copy of his two-page minority report, explaining his disagreements with the rating and concluding, "This combat veteran needs to be given the benefit of the doubt and be placed on TDRL [temporary disability retirement list] to continue additional rehabilitation and medical care." He told the Twohigs he hoped it would help.

Enervated, they left Walter Reed and started the long trip home. Richard was feeling sick.

"Do you want to stop?" Belinda asked.

"No, I just want to get the hell out of here."

So she paused just long enough for him to open the car door at a stop sign, lean out and vomit. Then she drove on.

RICHARD TWOHIG IS VERY QUIET on the 40-mile drive out to his mother's farm in Sweetwater, Tenn. It's the first time he has left the apartment in a couple of days.

Smoking Newports, he steers his SUV off the interstate, along a two-lane blacktop that climbs past fields of Queen Anne's lace and dairy cows in fenced pastures. Belinda first visited this area during a vacation in the Smokies, and bought her tract of fields, creeks and woodland six years ago. She hadn't expected to move here this soon, but now that seems the best solution for everyone.

Her plan is to raise, breed and sell alpacas. She already owns eight, currently boarded in Georgia while she prepares paddocks and barns. Richard, always an animal lover, has spent time learning to care for them. Alpacas are one of the few subjects for which he can, sometimes, summon real enthusiasm -- talking about how "they're real skittish" until you've worked with them for a while, how "they love kids," how their fleece comes in lots of colors, "gray, silver, black, white."

So Belinda's great hope is that he and the kids will move into a log cabin she's building on the property, where she can help raise her grandchildren while her son helps raise her flock.

"Daddy! Daddy!" Lizzie and Damon, who have spent the night with Belinda ("Grammy") and her fiance, Robert Rhyne, come dashing over as Twohig pulls into the drive. "Did you bring our water guns?"

"I didn't think of it," he says. He has a headache, one of the milder ones, but he sits on the front porch of the cabin -- Belinda and Robert are hanging kitchen cabinets inside -- and plays several rounds of tic-tac-toe with Lizzie. "No more," he says, after a few minutes. He watches Damon run his battery-powered truck up the pile of dirt next door to the cabin.

He and the children bounced around a good deal after his hearing and separation from the Army. The Veterans Affairs office in Winston-Salem, N.C., processed his benefits application at near-record speed -- probably helped along by an article in the Fayetteville Observer about his plight. The VA often assigns higher ratings; it uses the same guidelines as the military but applies them according to its own regulations and practices. It found Twohig 100 percent disabled, including a 50 percent rating for his headaches and 70 percent for his cognitive and mood disorder, with lower ratings for several other physical problems. "It is clear," its report says, "that you are unable to acquire and/or maintain substantially gainful employment in either a physical or sedentary setting . . ."

But while the VA began paying him $2,700 a month, it also -- by regulation -- deducted the Army's severance payment from his checks until the entire $12,000 was repaid. Unable to maintain a household on so little income, Richard sold the family's brick ranch in Fayetteville, and he and the kids lived for a while with his mother in Florida, then with his father in Tennessee and with Sang in Virginia. When he and Sang separated this past summer, they agreed that Richard should take the children because he wasn't working and could be at home.

He wouldn't get higher monthly income as a retiree than he currently gets from the VA. But TriCare insurance would let him see local civilian doctors; he would not have to drive nearly two hours to the VA hospital in Johnson City, Tenn. And it would cover Lizzie and Damon. Providing them with health insurance is the reason his estranged wife enlisted, so they're okay for now, but Sang has said she isn't loving the Navy. What happens if she leaves?

An appeal filed with the Physical Disability Agency was denied in April 2005, but Waple said he was willing to take Twohig's case to the ultimate level, the Army Board for the Correction of Military Records.

Even after Waple reduced his normal fee ("These people have been through hell," he explains), the appeal would cost another $2,500. "Mom, don't waste your money," Twohig urged. But Belinda considered that a reasonable investment if it brought her grandchildren health insurance until adulthood. "If I don't do this for the kids' sake, for their medical benefits, I'll regret it for the rest of my life," she decided.

So in July, Waple filed a petition arguing that the physical evaluation board failed to award the appropriate disability percentage, based on the regulations and the evidence presented. A decision could still be months away.

Belinda remains optimistic. "If I was sitting on that board and this was not my son, and I looked at everything," she says, "I would give him that 30 percent."

Meanwhile, the farm is taking shape. Belinda teaches ROTC in a Knoxville high school, and on weekends she and Robert, a jovial former contractor, do as much of the construction work themselves as they can. The main house, a dormered colonial of clapboard and fieldstone, is going up just across the meadow from the cabin. It will have three bedrooms upstairs and one on the main floor for Belinda's mother.

The cabin, where soon everyone is eating sandwiches and sitting on lawn chairs and upended spackle buckets on the porch, is just 400 square feet. Belinda can use it for meetings with prospective buyers and seminars on alpaca-raising. But it has a kitchen and a bathroom and could easily be expanded, which is her not-very-secret plan.

She's treading carefully, trying not to pressure Richard; she knows he needs to make his own decisions. She's mindful of the time she offered to ferry Lizzie to and from school each day -- the elementary school is near the high school where she's teaching -- and her son objected, "Mom, I have to have a purpose in life." Sometimes, beset by pain and depression, he says caring for his children is all that keeps him going. So Belinda hasn't pushed for a decision.

"I'm just in transition," Twohig says. "I don't know what I'm doing." In the coming months, as he turns 26, he'll move out to a rented house near the farm -- but not onto it.

Nevertheless, when Belinda stands on the porch and looks out at her property, a quiet haven without another house in sight, she envisions building a couple of bedrooms onto the cabin for Richard and the kids and the dog. He could help with the alpacas, with feeding and watering, shearing, trimming toenails. And when he had a bad day, Belinda and her mother would be just a few hundred feet away, ready to care for the kids until he recovered.

He'd never have to contend with crowds or noise or pressure or bosses. He could raise children and alpacas, and she'd have his back. He could, perhaps, be happy.

Paula Span, a contributing writer to the Magazine, can be reached at spanp@comcast.net. She will be fielding questions and comments about this article Monday at noon at washingtonpost.com/liveonline.