Officer Constant Pickett strolls a tree-lined beat along 17th Street NW these days, walking through relatively safe alleys where downtown office buildings look out onto apartment balconies.

From the doorway of the Cairo Liquor store at the corner of R Street, manager William Givens yells: "Hey, Connie, baby." Pickett, a handsome, square-jawed figure in blue, smiles and waves.

This is another world compared to Pickett's old beat -- the notorious 14th Street Strip -- just three blocks east, where he had worked for nearly two years as a foot soldier in Mayor Marion Barry's War on Heroin. When someone called his name in those days, he was more inclined to duck.

Some of the shootouts that have occurred on his old turf are legend. The most controversial involved his partner, Arthur Snyder, then 29, who was shot to death last year during a drug bust in an alley near 14th and U street NW. A few days later, Bruce Wazon Griffith, a suspect in the Snyder shooting, was himself shot to death by police following the largest manhunt in the city's history.

Pickett marched into the drug war two summers ago, after he volunteered for duty on a plainclothes tactical squad whose mission was to search and destroy the heroin flow through the back alleys and side streets Shaw and the 14the Street corridor.

He said he enjoyed being the "last line of defense," the cop on the street. He was among the first to be chosen after his commanding officer reviewed his record -- vice squad, gambling, perversion detail, more than 20 commendations, including the Gold Medal of Valor, the department's highest award, the rescuing seven people from a blazing building.

Today, Pickett, 34, says he just "burned out." With some modesty, but mostly frustration, he says the 400 or so arrests he made last year "didn't make a damn bit of difference." Heroin abuse continues to escalate along 14th Street, he says.

The psychological phenomenon popularly referred to as burnout -- meaning excessive frustration and exhaustion -- is not new, although among the nation's traditionally proud police forces it only recently is being acknowledged.

"There is a quality of macho ideals in police work," Walter Gorski, chief psychologist fot the National Association of Chiefs of Police, recently told The Chicago Tribune. "They are men raised in this culture not to be very expressive about their feelings, but rather to be the strong, silent types, to suffer in silence."

The D.C. police department recently set up an employe assistance program that offers counseling to policemen having personal problems. Department officials also are in the process of developing a 20-week program for new officers on how to cope with stress.

Police officials apparently have no statistics on the extent of the burnout problem on the force here. But, they say, as crime rises and some officers find a new boldness among criminals, police work increasingly is taking its toll on the force.

"The 3rd District [which includes both 17th and 14th streets] has always been one of the most stressful districts," said Deputy Cheif Isaac Fulwood. "It is one of the most diverse areas of the city. Trying to create an atmosphere where noncriminals can be safe takes its toll on commanders as well as men on the street. If a guy starts coming in late or boozing more than usual, or having complaints from his family, the commander will usually call him in for a chat."

Three months ago, Officer Pickett went to see his cammander for such a chat. They decided that Pickett needed reassignment out of the war zone, perhaps to a little rest and recuperation on 17th Street.

A child of Chicago's improverished Southside, the son of a nurse who familiarized him with the blood and guts of the emergency room at Cook County General Hospital, Pickett was a prime candidate for burnout.

Idealistic and eager to "help people," as he put it, he joined the department in 1969. He was 22, a former military policeman in the Army and a Vietnam veteran. He had been working as a lifeguard in Chicago when he met a young woman from Washington. Shortly afterwards, he recalls with a mischievous smile, "The trail from Chicago to Washington got hot." Eventually, Pickett moved here and married her.

Pickett was sworn in at a time when the police chief, Jerry V. Wilson, working in conjunction with the Nixon administration, was almost doubling the size of the police force in what Nixon often dubbed the crime capital of the nation. Wilson is credited with using the opportunity to hire more blacks, as well as a new breed of white officers who radically changed the department's "redneck" image among many blacks.

In those days, policemen were not always well received. One of Pickett's first assignments was to cover the 1971 May Day rally and massive antiwar protest. He watched a fellow officer flip over on his motor scooter and then, to Pickett's total astonishment, the hostile crowd descended upon the officer and began kicking him. Pickett himself lost control and waded into the crowd, fists flying.

Eventually Pickett became obsessed with police work, spending many extra hours on complicated undercover cases and gettng to know the city. His wife became increasingly critical, he said, and in 1977 the marriage ended.

Pickett's response was Cutty Sark Scotch. He developed a drinking problem, he says. Depression followed, but he still loved the work on the streets. By 1979, he had more than 20 citations and letters of commendation.

"I just make up my mind that I would be the best officer out there," he says today. "It was very hard. But in my own mind, I knew I had to do it. I had to try to make a comeback. I just couldn't let it keep me down.

"I was working as a dectective when my wife and I broke up, so I asked to go back to uniform. I guess I just like the way I look in a uniform."

When Mayor Barry announced his heroin war in 1979, drug overdoses had reached epidemic proportions. The rise in crime was being attributed largely to drug addicts, whose presence on street corners along 14th Street was too visible to ignore.

Pickett and established many street contacts during his days as an undercover officer. He knew he was a natural for the mayor's army. He was teamed up with Arthur Snyder, who, like Pickett, was an aggressive and dedicated officer.

Together they quickly established a reputation for using binoculars to observe drug traffickers undetected and then take them by surprise. Nine months later, Snyder was shot to death.

"When you get by yourself, there is a certain feeling of grief that comes over you, like an anvil around your neck," Pickett said, fingering the black tape stripped across his badge. It marked the recent shooting death of another officer. "You see death and destruction and you have to stay with it until the morgue wagon comes."

Walking the serene beat of 17th Street offers some solace from the hauntging memories.Sipping free coffee at the Fox and Hounds Lounge, a neighborhood bar at 1533 17th St. NW, Pickett says with some embarassment, "I'm still not used to people being nice to me."

There are four liquor stores on Pickett's new beat. They all love to see him, especially at closing time. So closing times are staggered until he arrives.

"We heard about you," Bill Givens of the Cairo said to Pickett, referring to Snyder's death. "We know you've been out there. We know you know what to do."

"Just a helluva guy. But we can't take no chances," said Derek Prue, a liquor store employe, as he adjusted the 9 mm pistol in the belt of his pants.

"I know you know what to do," Picket told him.

Later, when the officers finish their shifts, the station house takes on the atmosphere of a football locker room and there is talk of the Bust of the Day. These days Pickett has little to say during thos discussions, or about his future, preferring to take life one day at a time.

"I wouldn't mind going back to 14th Street, because I know there is a need for more men and money over there," Picket said. "I'd go back tomorrow if asked, but if the shooting started again, I know somebody would say I was seeking vengeance. So I'll wait, take it easy.

"My record shows that I don't stay in one place too long anyway, because i don't see myself as getting stagnated. I'm trying to make rank [sergeant], but if I don't I won't worry about it. I figure that I'll have the 17th Street beat for a year -- and then I'll be gone somewhere else.

"Deep down," he said, "I miss the action."