Rube'n Blades is padding down the hallway of his apartment building toward the incinerator with a sack of garbage in each hand, just as if there weren't a stack of film scripts on his desk from panting movie makers who caught his film debut in "Crossover Dreams." Salt of the earth. Just a regular guy.

"Go in, make yourself comfortable," he calls over his shoulder. He's wearing a T-shirt and shorts and white sneakers with no discernible brand identification. Blades is not about to get into "some pop idol thing" just because he's one of the world's leading salsa stars, his last album sold phenomenally (for a salsa record in Spanish, anyway), and he's just played Carnegie Hall.

He is haunted by the notion, growing steadily more plausible as he grows steadily better known to English-speaking audiences, that he might himself cross over, sell out, go Anglo. "There he goes, pulling a Julio Iglesias, and we'll never see him again," he imagines his loyalists complaining even if he were to start singing in English -- let alone club around with Mick.

So he still lives here on the Upper West Side, the neighborhood he's frequented since first coming to New York 11 years ago, when it had more bodegas and fewer mesquite grills. He still goes home to Panama two or three times a year. And he makes sure that his album notes and the messages on his phone-answering machine are in Spanish (the latter with translation).

He's just a down-to-earth, unassuming fellow with a shiny, new master's in international law from Harvard and a forthright ambition to be president of Panama, who reads Orwell, sings duets with Linda Ronstadt and thinks it entirely possible that he'll be gunned down young, that's all. Just like anybody else.

He says he's not really like Rudy Veloz, the salsa singer he plays in "Crossover Dreams" (now playing at area theaters).. Veloz is Blades' nightmare: a musician willing to dump his girl, double-cross his friend and compromise his music for the promise of a spot on Billboard's top 20. It is Veloz and his like whom Blades has in mind when he excoriates "people that get into a certain position, social climb -- and then it's difficult to look down. They don't want to be reminded of what they escaped from."

Yet for 20 years Rube'n Blades has been alternately drawn to and repelled by the culture of this country, home of Hollywood and Harvard, where any young Latin boy can grow up to play stereotyped drug peddlers on TV. It both patronizes ("Such an articulate fellow; where did you learn English?" he mimics) and rewards him.

His father was a policeman, his mother an actress on radio soap operas. But Rube'n grew up wanting to be Frankie Lymon, harmonizing with the guys in echo-chamber stairwells in Panama City. "He was big, as big as anything has ever been there," Blades says, reclining on a small couch in his rather Lonely Guy apartment. Concert tours and law school have taken priority over interior decoration.

"There was a building called Audisio, a three-story building. The second floor was great. Our parents weren't exactly thrilled. They wanted us to be somebody. 'Go to school! What are you doing singing in hallways?' "

The scenario is straight out of a black and white movie starring Tuesday Weld. Blades saw those movies too. "One thing North Americans fail to understand -- you're not aware of how much impact you have down there," he explains. "We knew who Gene Vincent was. 'Heartbreak Hotel' hit earlier there than here. Remember," he adds with some pride, "Panama is a port, and things hit there first."

Yet other messages were also trickling south. Blades watched "Father Knows Best" ("Everyone was happy and they had ice cream in the icebox all the time"), but he also saw newspaper photographs of snarling police dogs in Little Rock, Ark. By the early '60s, "people began to perceive the ugly side of this culture we all loved and wanted to be part of. At the same time, we started looking at ourselves more."

Riots in the Canal Zone in 1964, in which 21 died after Americans refused to let high school students raise the Panamanian flag alongside the Stars and Stripes, foreclosed the prospects of a life in rock 'n' roll. "There were parents there with shotguns," Blades remembers. "Clubs, dogs. It ended up with the U.S. Army attacking Panamanians. We couldn't justify this. How would I feel as a Panamanian trying to act as if nothing had happened, when something had?"

So Blades left doo-wop behind, studied law at the University of Panama and, when he had time, sang with Afro-Cuban bands, always in Spanish. In the 20 albums he has recorded since, he has never sung an English lyric.

He first came to New York in 1970, when unrest closed the university and his brother, who was working for an airline, got him a cheap ticket. "I just kind of wandered around to see what I should do," he remembers. He made an album that fizzled, was tempted to stay on, then went home to finish law school.

He ended up an attorney at the national bank, but decided to give music another shot. Returning to New York in 1974, he hooked up with the leading salsa label, Fania Records -- though not in the capacity he'd envisioned. "They wouldn't record me," he says. "I had to push a cart full of mail from 57th and Broadway to 52nd Street every day."

Eventually, of course, he did make records, with leading Latin bands and on his own, writing his own songs, steadily shouldering aside the limits of the salsa form. Blades' latest albums (he left Fania after bitter disputes and now records for a mainstream label, Elektra) lace salsa's insistent rhythms with flavorings of rock and funk.

"Every Afro-Cuban band sounds alike," he complains. "The trumpet, the brass. Why do we have to copy what was being done in 1940?" He's substituted vibes and synthesizers; his numbers cook without steamrolling.

But his lyrics are what really set him apart. Precisely crafted portraits of lives in Central America and in the barrio, they led People magazine to call him a Latin cross between Randy Newman and Bruce Springsteen -- and led radio stations in Panama and Miami to ban some of his songs.

Already a folk hero on the streets of Panama City and East Harlem, his recent work has earned him exactly the sort of wider audience Rudy Veloz sold his soul for. And life, as a result, is growing more complicated.

Blades spent a recent afternoon lip-syncing a line for the antiapartheid "Sun City" video with John Oates and Lou Reed in Washington Square. In the process, he "finally got to meet Bruce Springsteen," an event he chats happily about until he realizes he's subordinating politics to hero worship, and stops. His new album, "Escen as," includes a duet with Linda Ronstadt, whom Blades calls "refreshingly unaffected." Meanwhile the film and television scripts continue to arrive.

Though Blades turns most down -- "Big films, big names, but playing what? Some lowlife. You need a heavy, get a Latin" -- he's intrigued despite himself. He should, he says, be taking acting classes.

He lights a cigarette. His mother back in Panama would slap him if she knew. He'd been clean for years, but Rudy Veloz smoked, so now Blades does too.

"I understand how many young Latin Americans are looking at what I'm doing, and I don't want to give the impression of abandoning them," Blades says again. And, "Panama is something that has never left me. I am its child."

He is going home one day, he has been saying for years, to help lead his country. He used to say, point-blank, that he wanted to be its president. He's grown slightly more circumspect these days, talking about "communication" instead of titles or agendas. "I can bring both sides to the table, the students and the working class, the private sector," he reasons. "I'm probably one of the most recognized Panamanians, after the president and the head of the military and boxer Roberto Duran. I have access to the media. The people know what I'm singing about and that I haven't changed.

"But I'm not just some dingbat musician trying to save the world. I have credentials."

He calls his education "an intellectual .45 you can carry with you." Yet the Harvard degree he's counting on to bolster his political credibility was hard-won. When Blades arrived in Cambridge a year ago, after a long hiatus from higher education, he'd never studied in English. "The first few weeks I kept asking myself, "What am I doing here? What am I trying to prove? Am I trying to legitimize myself with this? Am I an arrogant idiot?' . . . I felt like crying; I was just scared." His mother went to Cambridge to watch him graduate (he'd skipped his law-school commencement in Panama); so did a British film crew doing a documentary.

He wants the visibility -- though he fears publicity's toll -- to promote his point of view and his political ambitions. So when Panama's censorship committee banned one of the songs from his album "Buscando America" (saying that "Decisiones," the ruminations of a pregnant teen-ager, promoted abortion), Blades just laughed.

"It was headlines for two weeks," he crows. "The tapes were everywhere. Buses played it, loud. I went there to perform and 20,000 people came, the largest crowd ever for a nonpolitical event. You ever hear 20,000 people singing a song? You think they didn't hear 'Decisiones'?"

Being banned in Miami, that's another matter. Blades is politically progressive but unaligned; he's never joined a party. To have Latin radio programmers decide that an anti-interventionist song called "Tiburo'n" ("The Shark") was a procommunist statement infuriated him.

"Some Cubans in Miami have a very particular view of dictatorship," he fumes. "They attack Castro's but not Duvalier's. They talk about political prisoners in Cuba but not in Chile. They would applaud an invasion of Nicaragua but remained conspicuously silent for years about Somoza. They complain about the repressive regime in Cuba, but they ban my records . . . And anyone who points these things out is branded a communist." He's pacing now. "I resent it with all my heart."

And, of course, things happen to Latin American political activists who, rightly or wrongly, are labeled communist. Panama has had a frightening autumn: The president resigned under military pressure; a prominent opponent of the military was found decapitated; another activist was kidnaped. Life is starting to sound eerily like a Rube'n Blades song.

"I'm going regardless," he insists. "You have certain responsibilities. I think I can help clear issues, bring people together; that's what I'm here for." Yet he doesn't expect to grow old. He's felt this way since he was a kid, which may be why he's never married or fathered a child.

"The way the world is today? Hijackings and senseless killings? John Lennon getting shot by a fan? I'm not a pessimist, but I'm not inventing these things. If you're in Latin America and dealing with the possibility of change, you don't know . . . They smell communism and that's it for you, and you don't even know who hit you."

Then again, he adds, "I may leave and come again." His grandmother believed that she had been, in other lives, a slave in the Confederacy, a Roman soldier and a French courtesan. "I just hope I don't come back as Howard Cosell," Blades says, sounding more like someone from Jersey City than from Panama City.

Still, he remains so uneasy about crossing over that when he finally gets around to recording an album in English, he plans to invent another persona -- "Panama Blades" -- to record it. He's attracted to "the possibility of a Latin who breaks the stereotypes, talks to Americans and Europeans in their own language, not something exotic." But Panama won't look or sound like Rube'n, who doesn't want to tour Latin America with his band and be asked to sing in English. "You create a very schizophrenic audience. It could create some kind of friction," he says vaguely. "There's this pride."

So is it Rube'n Blades or Panama Blades who, after discussing his correspondence with Gabriel Garcia Marquez and his plan to write songs based on six Marquez stories, politely asks if he might flick on the television? "I hate the Cardinals because they bombed the Mets," he mutters.

He takes a Lonely Guy dinner -- something crimson in an aluminum dish -- from his oven and pours a glass of cranberry juice. "Salisbury steak, so it claims," he says, poking a fork at the food. And, setting his meal atop a script on the coffee table, he sits down to watch the game.