Kinney and Crescencia Owens, grimy and disheartened from too many nights in their station wagon, stopped at the Depot shelter here last winter hoping just to use the shower. They were refused.

"We thought somebody else could use the bed 'cause we had the car, and warm clothes and warm blankets," said Crescencia, pushing back her long brown hair. Even though the little 20-bed shelter was often overbooked, the rule was that only overnight guests could use the shower, so the Owenses reluctantly moved in, unhappy victims of one more bureaucratic complication in the national effort to help the homeless.

Through more than two years and the expenditure of $210 million in federal dollars, shelter operators, members of Congress, homeless advocates and agency officials have been trying to ease the pain and discomfort of hundreds of thousands of derelicts. But that effort is now so embroiled in political controversy, cumbersome rules and contradictory programs that the practical problems of individual homeless people seem to have receded into the background.

Faced with reports of people sleeping under bridges and in cars and a rising influx at existing shelters, Congress created the Emergency Food and Shelter Program in March 1983. It provided money for feeding and housing derelicts in mostly privately run shelters while federal departments and committees worked out ways to address the root causes of the perceived spurt in homelessness.

The instinct of government, even under a president distrustful of social engineering, was to act, but today the effort appears mired in confusion over what forces have caused homelessness and whether any of them are within the government's power. Before taking its summer recess, the House approved a $70 million appropriation for emergency food and shelter programs in fiscal 1986, carrying over the amount spent by the Federal Emergency Management Agency the previous year.

"It's best to take their money but not take their systems," said Cindy Abbott, director of the Depot shelter, which has some federal support. Even the federal requirements for accepting funds often "miss the point of what we're doing" and volunteers are "less likely to get burned out" than federal workers, she said. Her experience, and the government's failure to do much more than try to keep the homeless sheltered and fed, has appeared to add strength to the many voices arguing that government should curb its instinct to act in such cases.

Many homeless people who are mentally ill appear determined to reject whatever institutions and programs are available to them. Popular efforts to help some poor people by rebuilding downtown neighborhoods have put many other poor people on the streets. Family disputes, the cause of homelessness for many, resist political solution. Welfare officials' efforts to discourage cheating have led thousands of homeless to shun public relief and shelter and choose less-regulated, if often overcrowded, private shelters like the Depot here in this Los Angeles suburb.

The problems the homeless most often mention have to do with the running of shelters, annoyances like the no drop-in showers rules or a lack of telephones, and must be handled by shelter supervisors.

Adding to the accumulating obstacles to help for the homeless is the old story of neighborhood resistance. In scores of communities across the country plans for new shelters or training facilities are being opposed by businessmen and residents who feel that the presence of ill-kept poor people, many of them alcoholic and mentally ill, will drive away customers and lower real estate values.

Democrats have blamed homelessness on a Republican administration in Washington that has allowed high unemployment to fight inflation and encouraged welfare cuts. But housing experts say the roots of homelessness are often far less political and less susceptible to political solution.

In several local communities, for example, leading Democrats as well as Republicans have applauded the downtown revitalization projects that have replaced thousands of inexpensive rented rooms with office buildings and glittery hotels. Private shelters like Pasadena's Depot or downtown Los Angeles' Midnight Mission have had to absorb the displaced persons who once lived in cheap, $6-a-night residential hotels, sometimes called SROs (single room occupancy.) New York's supply of such hotel rooms dropped from 50,000 to 19,619 in several years. San Francisco lost 10,000 rooms in the 1970s; Los Angeles lost 7,000.

Little has been done to replace this housing, and what is left is not good.

"There is a radiator in my room. It has never been on," James Simpson, a Los Angeles welfare recipient assigned to the Russ Hotel, said in a court declaration filed in December. "I asked the guy at the desk to turn on the heat when it got real cold. He just looked at me."

The family problems that lead to homelessness are also rarely fit topics for political debate. Kinney and Crescencia Owens, the couple who wanted to take showers at the Depot, are one example. They slept in their creaking station wagon in a church parking lot not far from the shelter. They were in the streets because Crescencia's father had ejected them from his spacious house in Fontana, 50 miles to the east.

Kinney said he had lost his $40,000-a-year job as a sound technician after a dispute over an unpaid bill reached his studio's main office. When he and Crescencia separated briefly, a man she dated beat her so badly that she had to be hospitalized. Kinney helped nurse his wife back to health, but her father and sister tired of having them in the house. They lived in their car and tried to make a living selling small items at swap meets and flea markets.

When such family difficulties result in severe mental illness, policy makers in Washington rejoin the discussion. Both liberals and conservatives have recommended improving community mental health care facilities, although who would pay for this is not clear. But if there were money to build a new mental health clinic next to the Depot, it still might not help someone like Larry Ingle, an independent-minded American University dropout.

By his own count, Ingle has been committed four times for schizophrenia. The last and longest hospitalization, eight months, was nine years ago. Since then he has wandered about, arriving in California in October to look for work or schooling.

"I had to do something drastic," said Ingle, 34, a tall, slim figure dressed in a long, dark winter coat and chewing on a piece of bread at Pasadena's soup kitchen. "My family, they always sort of babied me. They felt like they should protect me. But, you know, I have to sort of make it on my own."

Dr. Ellen L. Bassuk, a Boston psychiatrist, found "a 90 percent incidence of diagnosable mental illness" in one large Boston shelter in 1983. Her new study of homeless families indicates that more than 60 percent of the mothers could benefit from psychiatric care.

Other researchers have challenged these high percentages. "I could find a diagnostic category for just about everybody I know," said Richard Ropers of UCLA, whose own samples of homeless here show only about 20 percent with a history of mental illness.

But no matter how many street people have emotional problems, whether they can be forced to seek lp if they don't appear to want it remains a thorny issue. The federal courts have decreed that the homeless mentally ill have a right to the independence that is their often-expressed goal.

Otis McLaughlin stopped at the Depot and proclaimed himself a fugitive from Eureka, Calif., where he said a "personal war" against "folks from out of state" was under way, part of a plot by Canada to take over the United States. He had apparently harmed no one in his journey. His words were harsh and disturbing and he presented an odd picture in long coat, tennis shoes and graying crew cut.

Ten years ago, in the case of O'Connor v. Donaldson, Supreme Court Justice Potter Stewart anticipated the situation of people like McLaughlin by proclaiming a constitutional "right to liberty" for the emotionally disturbed: "May the state fence in the harmless mentally ill solely to save its citizens from exposure to those whose ways are different? One might as well ask if the state, to avoid public unease, could incarcerate all who are physically unattractive or socially eccentric."

For many homeless, the welfare system seems no more attractive an option than a mental health clinic. Los Angeles County, under its general relief program, will pay a single person with no other means of support $228 a month, plus food stamps, bus tokens and free care at the county hospital. To earn that, an able-bodied recipient must clean up county parks and hospitals or do other public service work 16 hours a week and visit at least 20 prospective employers each month.

Those who do not comply are cut off for at least two months before they can apply again. Carol Matsui, special assistant to the director of county public social services, estimates that about 2,000 of the nearly 36,000 on general relief are forced off the rolls each month for disobeying the rules. Ropers insists that the number is much higher: "The general relief system and the whole welfare system throws up a whole lot of obstacles to needy people."

The Owenses did not apply for general relief because they would have been forced to sell their car, their only source of mobility and guaranteed shelter in an uncertain world.

The reluctance to deal with the welfare system persists even though, according to a recent county analysis of federal data, general relief grants in Los Angeles are larger than in most other cities and states. The District of Columbia provides only $206 in monthly general public assistance to indigents who can prove medical disability; healthy applicants get nothing. General relief in Montgomery County pays a maximum of $235.30 a month. Fairfax County pays $225 a month, but for only three months.

When asked what they would like improved, homeless people often mention inadequate services at the shelters they frequent. Many complain that they cannot communicate with the outside world -- the potential employers, caseworkers, family and friends who might help them. One pay telephone serves Pasadena's Union Station soup kitchen, where homeless people congregate during the day. There are no phones they can use in the overnight shelter, and they are only allowed to be there from 10 p.m. to 6 a.m., when calls are inconvenient.

Jerome Brown, an unemployed office clerk and messenger, said, "I could have worked today if I was in someplace stable, someplace where I could call them, they could call me." The pay phone at Pasadena's soup kitchen was "very inconvenient," he said. Kinney Owens said he would like to stay in touch with his union about new jobs, but "we have no telephone in the car. And when you've got to put 45 to 50 cents per call several times a day, it can add up."

Some shelters are trying to respond to such complaints. A recent city-neighborhood agreement in Pasadena, now challenged in court, would allow the construction of a new 40-bed shelter with shower and phone privileges for homeless who don't want to stay. Bill Doulos, director of the Union Station soup kitchen, said he hopes the telephone company will be able to give him a special line that will permit local, but not long-distance, calls by derelicts seeking jobs and housing.

Most shelter providers approach the future with little more financial certainty than their homeless clients. Although the House passed the $70 million appropriation for fiscal 1986, the Senate must still take action. "I get a hundred calls a day from people all around the country asking what I've heard," said William I. Fields, a United Way executive who staffs the Alexandria-based Emergency Food and Shelter Program that disperses homeless aid.

Congressional advocates for the homeless have said they would like to provide money for more community mental health programs for those with emotional problems, more job training for the unskilled, more efforts to save cheap housing downtown. But so little is known about how the homeless would respond to such programs, and there has been so much resistance to new homeless facilities or even to counting the homeless, that some experts wonder how much good the additional money will do.

"I think most of the homeless are unaware of what goes on in the political arena in their name," said Anna Kondratas, who recently wrote a report on homelessness for the Heritage Foundation. When more federal dollars are added, "at the margin, you get some more to use the system, . . . but homelessness can't be solved without the massive intervention of volunteers."

She added: "One couple operating a shelter told me what the people need is very tough love, and you can't get that from a federal program."