Buffy Sainte-Marie is a flashy performer nowadays, at least by the serious acoustic standards of 10 years ago.

A disco dress has replaced the peasant blouse, and while the acoustic guitar is still evident, it is backed up by a slick, five-piece band on country tunes. "Powwow rock," even on an occasional disco number.

Ten years ago, in the rhetorical heat of the 1960s, this daughter of a Cree Indian reservation was a protest singer, a "Movement" figure, a musical force spoken of in the same breath with Dylan and Ochs and Baez.

Ten years ago, Buffy Sainte-Marie wrote anthems for an angry decade. "Universal Soldier" and "Now That the Buffalo's Gone," sung in her riveting vibrato, were protest standards. Sainte-Marie posted for countless festivals and rallies, staged benefits for the burgeoning Indian movement, and recorded dozens of albums.

Then, Buffy Sainte-Marie disappeared.

"What you're looking at is an international star and an American secret," says Sainte-Marie with a wide grin. "The past few years have been good to me, so I'm not complaining. I've had great success in Europe and the Far East and Canada, so if I'm thought of as an alternative performer, it's only in my own country."

The singer is 36 now, married to a Sioux artist, and mother of Dakota Starblanket Wolfchild - age 20 months. This Washington date is her first in four years (a two-nighter at the Celler Door earlier this week, and Kennedy Center benefits today and tomorrow).

"I don't have an album out or a conglomerate record company backing me," says Sainte Marie, "but I do have a great band now, and lots of work, lots of dates. And I'm still a big star with kids in airports."

The airport notoriety comes from Sainte-Marie's three seasons as a regular on "Sesame Street." "I've been living in Hawaii, and performing all over the world, so my exposure here has been limited to the work on 'Sesame Street.'

"The show is important to me because children watching learn that Indian people have languages and counting and numbers.Talking to Big Bird and other characters, i can prove to children that the Indians aren't all dead, or that they're all the same."

"Sesame Street" seems a leap of faith from the Network Folk Festival and the antiwar movement, but Sainte-Marie sees it as all of a piece. "I'm satisfied. I'm reaching people on television and in live performance in a way that, say, Olivia Newton John is not.

"The music I'm doing now," says Sainte-Marie, "is more appreachable, more touchable than it was in the '60s. At one point, I was trying to show my audience how to help Indian people out. Now, I'm trying to share more of my own personal feeling. The songs are a little different, but they come from the same place."

Sainte-Marie feels comfortable, not irriated, with these quiet times.

"Sometimes, when I think about it, it occurs to me that the '60s were a fad. A good fad, in terms of things like raising people's consciousness, but still a fad.

"Now," says Sainte-Marie, "I feel as though the bandwagon might be filled with people who want to dance, to feel good. And it's not all that different from the '60s. People were trying very hard to feel good then.

"I'm doing more up-tempo, good-feeling songs and I suppose that's a reflection of the times.

"When I play at an Indian reservation now, the young people don't want or need to hear bitterness. They live with that, and they understand it. What they want to do is sniff out the joy, and as a performer, I have to give them that."

Sainte-Marie has recently bought up the rights to her albums, and hopes to reissue them under her own label. Affer a decade of artistic exile, Buffy Sainte-Marie is trying to come home.

"You can't live on bitterness," says Sainte-Marie, "particularly is you're caught between two cultures.

"At one time, a few years ago, what you had to do was scream for help. Now, you have to take a look at the lives of Indian people, and offer a sense of our own joy, our own beauty."

"Buffy Saint-Marie still writes her music for the strivers, the dreamers. Her road show is more polished now, with sequins and boogie-down touches, but the emphasis hasn't changed.

No one has convinced her that using music to combat injustice is a fad. No one has convinced her that audiences will not listen to her message. In a sense, Buffy Sainte-Marie hasn't changed at all.

"It's a time to move from Idnian as victim to Indian triumphant."