"Let Freedom Sing!" started out in Philadelphia as a musical revue celebrating the 200th birthday of the Constitution. But somewhere in the course of its development, it seems to have acquired the satirical ambitions of a cabaret show. The results, which are on view in the Kennedy Center's Terrace Theater for the next five weeks, are decidedly mixed, not to say all mixed up.

On the one hand, this two-hour evening will remind you of a well-intentioned high school teacher who wants to make the Constitution come alive for his students and is willing to dress up and tell jokes to achieve his goal. Learning is supposed to be fun, you can hear the show saying to itself, and history needn't be dry as sawdust.

On the other hand, "Let Freedom Sing!" would like to be smart and savvy about our confused times, and it trains a mocking eye on such issues as abortion, school prayer, yuppie materialism, immigration and the Equal Rights Amendment. At such moments, the mood is far less benevolent. Although the material never cuts to the quick, it makes a few slashing gestures. Then, as if to tie up so many disparate impulses, the five cast members conclude that, imperfect though the Constitution may be, "you gotta love it -- warts and all."

Loving this show, warts and all, is a tougher assignment. When the material is at its best, which is about 25 percent of the time, it's okay. When it's not, even the briskness of the performers and a lively staging can't relieve the spreading torpor. Lacking the courage of its patriotic convictions, the revue isn't particularly uplifting. And yet whenever it unleashes a satirical barb, it feels compelled to apologize afterward, as if to say the kidding is really just in good fun. The best satire doesn't try to be ingratiating; it lets the chips tumble where they may.

Some 30 composers and writers have contributed to the revue -- among them such established talents as Stephen Schwartz, Sheldon Harnick, Alan Menken and George C. Wolfe. John Phillip Sousa's "Stars and Stripes Forever" has been equipped with new lyrics, extolling our right to disagree with our neighbor's opinions while defending his right to express them. And David Crane, Marta Kauffman and Paul Lazarus have written half a dozen or so sketches to break up the musical proceedings.

Out of this patchwork has been forged a patchwork; there doesn't seem to be an overriding point of view. Take "School Prayer," for example, in which the company members, playing high school students, implore God to "Let me score," "Let it be only a sore" and "Let me kick the habit." Just what's being addressed here -- the trivialization of prayer or its crying need in today's classroom? Or maybe the hopelessness of today's teen-agers? Darned if I can say.

There's a point to "The Immigration Policy Song," which satirizes our arbitrary immigration laws. But having Jenifer Lewis play the Statue of Liberty as a hooker whose price varies according to the nationality of the would-be client may not be the best way to make it. Contemplating the poor, huddled masses, yearning to breathe free, she observes tartly, "No girl can turn that many tricks."

Even Dee Hoty, who strikes me as the keenest of the five performers, can't triumph over "It Doesn't Concern Me." As she sings gaily about her lack of interest in constitutional safeguards -- aerobics class is foremost on her mind -- three backup singers bind her hands, hang weights about her neck, blindfold and ultimately gag her. For being obvious, it's sure obvious.

"A Little War" allows the three men in the cast -- James Judy, Stephen James and Alan Weeks -- to score as various presidents sidestepping Congress and initiating military action around the globe. And there's a clever sketch in which the men play teary beauty pageant contestants, vying for the title of Mr. President. But they, too, have to plow through their share of junk -- sometimes as bewildered patriots and avaricious lawyers at the Constitutional Convention, sometimes as latter-day nerds and zealots.

The show has been outfitted with some snappy scenery by James Leonard Joy and natty costumes by Nancy L. Konrardy. This is what revues used to look like when the theater was in the regular business of producing them. But the genre has long since fallen on hard times, a victim of television, which is quicker on the draw.

It doesn't help that "Let Freedom Sing!" can't make up its mind what it really wants to do -- castigate or celebrate. Wrapping the evening in the Constitution doesn't disguise the underlying mishmash. The agenda includes Ben Franklin, Vanna White, Fred and Ginger, Dolley Madison, Judge Bork, apathy, slavery, bigotry, sexism, urine tests and Japanese industry.

The payoffs make for a much shorter list. Let Freedom Sing!, conceived by David Crane, Marta Kauffman and Paul Lazarus. Directed by Paul Lazarus. Choreography, William Fleet Lively; musical conductor, Michael Skloff. With Dee Hoty, Stephen James, James Judy, Jenifer Lewis, Alan Weeks. At the Kennedy Center's Terrace Theater through Jan. 30.