I'LL TELL you one thought I've had in my old age," says Paul Newman, stretched out on a sofa, staring into the future. "The corruption of the American actor. I always knew it happened to others, but I never knew until now that it could happen to me. It's not the money, I don't have to worry about money. It's that you start thinking of yourself as a movie star rather than an actor."

The last two or three years have been rough, but his own admission the low point in his career. "And some personal pain too," which is the closest from a drug overdose. He's just turned 55 and is taking stock of his life.

He says it's the surest sign of corruption when an actor thinks he's "above going back" to the stage, which is where he started. So he's determined to return soon, for the first time in 15 years. His last stage appearance was in the Broadway production of "Baby Wants a Kiss," with his wife Joanne Woodward. For the first time in as many years he's hired an agent to help focus his career. And only recently has he activated his own production company in an effort to develop projects in which he can star or direct, such as the made-for-TV movie "The Shadow Box," which aired in December and marked his TV directorial debut.

He complains that too few good roles are written anymore, and that fewer still fit the mold American audiences set for their superstars. "In the last analysis, you have to develop your own projects, and I've never been good at this."

On this day, he's in somebody else's project -- on location in Miami, starring with Sally Field in Sidney Pollack's "Absence of Malice," in which he plays the victim of an inaccurate news leak. "But seated in his trailer, surrounded by classical music and holding a novel that he guickly hides from view, he is more interested in reaction to "Ft. Apache, The Bronx," which opens here on Friday.

In the movie, which deals with a police precinct in New York's embattled South Bronx, Newman plays a cop named Urphy, an 18-year veteran of the precinct who alone among the cops in the film demonstrates compassion for the black and Hispanic residents of the community. He says he initially was struck by the role because the character was more flamboyant than those he's played in the past.

He's the first to admit that he's made some dumb choices and some rotten movies over the past decade, including "WUSA," "The Mackintosh Man" and "The Drowning Pool."

"I made a couple of really bad ones back to back," he says soberly of his last two films. He believes "The Day the World Ended," a disaster movie about volcanoes, was "a terrible mistake" he made because he wanted to do "a big, commerical film." And he calls the choice of Robert Altman's "Quintet," a critical disaster about life in an ice age, "whimsical."

"Probably I choose my films for a lot of the wrong reasons. If I'm not working, I'll choose a script because it happens to be around, even though it might be worse than one that came to me five months before, when I was working." A close associate of Newman's says he's also taken roles to lend filmmaker friends support or to return a favor. And he's regularly turned down films that conflict with his commitment to race stock cars during summers. All of which leads one to wonder how much he cares.

"Of course I care! Listen, every actor alive wants to do critical blockbusters," he says, but believes that good projects are rare.

But there must be some good roles he's passed by.

"Yes. I turned down 'All That Jazz,' which was a great mistake. I didn't think the character [which won Ray Scheider an Oscar nomination last year] was redeemable. And, of course, I didn't take Bob Fosse [the director] into consideration. It was a dumb, dumb mistake!"

He also turned down the role played by Al Pacino a few years back in "Bobby Deerfield", an irony, since Pacino was Pollack's first choice for "Absence of Malice." And he says he's turned down roles played by Redford, and vice versa. But all this, he says, is beside the point.

"All I know is, 20 years ago I spent 15 percent of my time reading for the business and 85 percent reading for my own pleasure, and now it's the reverse. Over a year, I'll read 200 scripts," says Newman, who gets $1-3 million per film, but says he'll do the right one for nothing, "and I keep turning them down. This must say something about what's going on in the business."

Newman regards the '60s, when he was Hollywood's leading male star, as the high point in his career, when three of his favorite films -- "The Hustler," "Hud," "Cool Hand Luke" -- brought his Oscar nominations. "God, it doesn't seem long ago!"

Reminded of his other nomination, for "Cat on a Hot Tin Roof," he demurs, "Nah, that was too early. But there really were interesting films made in those days. The kind of picture I want to do and enjoy doing aren't fashionable today. You know, if 'Rachel, Rachel' came out today," he says of the small, somber 1968 film starring Joanne Woodward, with which he made a distinguished debut as a director, "I don't think audiences today can focus on anything for more than the distance between commercials.

"But another reason is the writing. The old writers have written themselves out and the young ones have a lot of viscera, but not a thread of intelligence in their work. There are obvious exceptions.

"I saw 'Raging Bull' the other night and it wiped me out. I sat down and wrote [Martin] Scorsese and [Robert] De Niro and I never do that."

He says he was surprised that he liked "Ordinary People," because when Robert Redford, who developed and directed the film, first showed him the script, "I did not like it at all, I would have advised him not to touch it." s

A few years ago, Newman says, he optioned a controversial novel called "The Front Runner," in which he would have played a homosexual. He says the sexuality was no problem for him: "I just don't know whether I would have been accepted in that role." And he points with pride to "Slapshot," which didn't do too well at the box office when it was released three years ago, but for which Newman received good reviews as an aging ice hockey coach desperately trying to come to grips with his future. "It may not have been the best movie I ever made, but it was the most original role I'd played in years."

Since "Rachel, Rachel!" he has directed only two feature films and "The Shadow Box" for television. "I'm more selective about what I direct than about what I act in," he says. And like "Rachel," a film about lonliness, each of the projects has been surrounded by a certain grimness.

"If there's anything I'm interested in, in this anesthetized society, it's motion," he says. "I want to really get to an audience and wake them up. i

"As people feel more and more threatened, in order not to collapse, they have to anesthetize themselves. Every American male is castrated, just like every Russian male, because you can't protect you family when the enemy is invisible," he says, alluding to the nuclear weapons he's been cautioning against for years. "Another thing that anesthetizes them is the fact that there are no solutions. Technology, history are out of control. And that's threatening. You want to dig a hole and pull the ground in over yourself."

Despite his well-known liberal politics, Newman found himself at the center of controversy over "Fort Apache." Members of the Hispanic community are still protesting, as they did last spring when the film ws being shot in New York, against what they believe to be negative, sterotyped portrayals.

Newman is enraged at the protesters. "I don't like being called a racist pig and being told I give up my humanity for money. Maybe they're looking for a political base or to call attention to themselves in their community." Hispanic leaders point to the fact that there are no upstanding Puerto Rican or black characters in the film.

Susan Newman, a daughter by his previous marriage, says in a new book by Kathy Cronkite about celebrity children, that her father is "isolated from the real world." Newman typically unflappable, says that the estimation is probably fair.

Meanwhile, he has no sure solution to becoming an incorruptible actor; and after he completes shooting "Absence of Malice" this month he has no firm plans. "I've never had much of a plan, which may be a kind of a plan after all. A lot of guys have big plans, but their plans start running them, so they can't really do anything. They're immobilized. They can't direct themselves."