"It can so" is the logical motto for the life and career of Arthur Mitchell. That's the answer he's stubbornly given all the countless times he's heard the phrase "it can't be done." Black dancers aren't suited to classical ballet, they said. So he turned himself into one of the New York City Ballet's most fabled soloists, creating roles in such Balanchine masterworks as "A Midsummer Night's Dream" and "Agon," in performances thereafter firmly ensconced in ballet legend. A black ballet company could never compete against the establishment, they said. So Mitchell and colleague Karel Shook founded the Dance Theatre of Harlem 13 years ago, and nursed it carefully toward the heights of fame and critical esteem. A black company, they said, would always remain "special," outside the mainstream. So Mitchell has now seen to it that this last barrier has been vanquished as well.

The results of these efforts are on display this week at the Kennedy Center Opera House, where the DTH is performing in the Dance America series, presenting five Washington premieres and other repertory. Mitchell talked about the company and where it's headed a few days ago in his Washington hotel room. In his natty suede jacket, as slender and handsome as ever, he looks like a walking advertisement for health food or right living or both. Next month he'll celebrate his 48th birthday--it'll be a triumph of deceptive appearances.

"In the last two years," he says, "the company has just skyrocketed. Even since the beginning of last season, the growth has been immeasurable. The big change was our Covent Garden seasons in London--that was a major breakthrough. For the first time, 'blackness' wasn't even discussed--we were treated simply as artists. Some of the English critics said we'd outgrown some of our early repertory, that there was nothing left we had to prove. It was this very feeling that reflected itself in the company dancing, down to the last kid in the corps de ballet."

Mitchell hadn't yet seen Clive Barnes' article in the current Ballet News, accusing the nation's major white-dominated classical troupes of racial "tokenism," but he'd heard about it. "The ironic thing," Mitchell says, "is that the black dancers these companies have acquired--Paul Russell at the San Francisco Ballet, Mel Tomlinson at New York City Ballet, Ronald Perry of American Ballet Theatre--all came from DTH." Mitchell regards this as a tribute to the training provided in his school and company both, but it's something of a wrench--on both sides--when a dancer carefully groomed by Mitchell and Shook ups and leaves for one of the other biggie companies. "I'm such a dominant person, really a father figure for them," he says, "that I think they're nervous about making a break, and especially about coming to tell me about it. But the ties are still there, and they keep hanging around afterward. After all, they've left a close, family-like situation, and gone to troupes where they don't have the same kind of togetherness and camaraderie--it's tough to be a pioneer, and that's what they are."

Never one to duck challenge, Mitchell has been leading the troupe recently in still another direction, veering aside in the company's new repertory from strict classicism towards ballets in a more dramatic or contemporary vein, like the revival of Valerie Bettis' "A Streetcar Named Desire," or John Taras' new version of "Firebird." "Sure this is something of a change for us," says Mitchell, "but I began to see that one of the great virtues of the American dancer is unparalleled versatility, and I saw the need to develop this side of the company as another stride toward artistic maturity. There's an irony here, too. When defectors come from other countries, like the Soviet Union, and they break their necks to do all kinds of dancing--Broadway, jazz, modern dance--they're praised for their daring, and their versatility is acclaimed as a virtue. When we do something similar--to expand our horizons, just as they wanted to expand theirs, it's the reason they came here--we're criticized for being eclectic, and somehow our versatility becomes a negative value. It doesn't make sense."

Mitchell picked "Streetcar," first mounted in 1952, because "no one's done it in a while; it's an American stage classic with box-office appeal; and because I visualized Blanche DuBois as an ideal vehicle for Virginia Johnson. Bettis and Fred Franklin did the staging for us; Bettis asked Tennessee Williams what he thought of the idea of doing it with an all-black cast, and he told her it was wonderful, fascinating." The Taras "Firebird," meanwhile, has been chosen as the centerpiece for a program in the "Kennedy Center Tonight" TV series--the production will be filmed here during the Opera House run, and aired in early May, along with documentary material on the company shot earlier in New York.

As ever, Mitchell is keeping one eye on the future. "Agnes de Mille has said she'll give us 'Fall River Legend,' " he says, "and Eugene Loring wants to stage 'Billy the Kid' for the company. We're also negotiating to get Bronislava Nijinska's 'Les Biches,' and I'd like to add 'Graduation Ball' too. What we're doing is going after all the stuff from Ballet Theatre, the old Ballet Russe, and from Balanchine that added up to the concept of 'dance-theater,' which is what we're all about. And of course, I still want to do my 'Giselle' production with the story transferred to Louisiana. Giselle a slave or freed slave, and Albrecht a Creole--you know, with the Spanish moss and the bayous and the legends, they've got all the same ingredients there that gave rise to the original 'Giselle' story, but this way it would be really viable and natural for DTH. Sure, it's a risk not doing it the old way, but that's the kind of chance I've always been willing to take."