Philadelphia Festival Theatre for New Plays at Annenberg Center, 3680 Walnut St., through May 19 (898- 6791).

I'll bet you didn't know you spoke fluent Yiddish.

Of course the real actors, in Philadelphia in 1996, are speaking English. But in accepting the pretense that Yiddish is our shared language, we in the real audience, pretending to be the audience in Vilna in 1899, are instantly incorporated into the fiction of the play-outside-the-play-within-the-play, and simultaneously implicated in the cultural politics of Joselovitz's fascinating play.

For Vilna's Got a Golem is about the politics of resistance, and about the complex problems of its theatrical representation - problems that we, as audience members, share by our very act of watching.

The actors we see are staging (on the stage-within-a-stage of David P. Gordon's set) a play about the Jews of Vilna in 1540, a time of rampant anti-semitism, for an audience of Jews of Vilna in 1899, when the actors and the audience alike have just experienced yet another murderous round of pogroms.

Zebi (David Ingram), the head of the theatre company staging a play about violent resistance written by his brother, plays Zebi, a sixteenth-century cobbler who helps his brother build a Golem, an automaton of mud and chickenwire, the embodiment of violent resistance. His brother Zavel (Benjamin Lloyd), who has suffered an unspecified emotionally-crippling loss in the latest pogrom, plays Zavel, a sixteenth-century cobbler whose pregnant wife has been brutally murdered.

The emotional needs of the actor and the character merge, until we cannot be sure whether it is Zavel the actor or Zavel the character who refuses to waiver from his scenario of vengeance, or whether it is the actor playing the Golem (Michael Nichols) or the Golem itself who walks off the stage and out of the theatre.

The rabbi in the play-within-the-play, trying to dissuade the cobbler brothers from building a Golem, explains that the Golem is only a metaphor. Not so in the play-within-the-play, in which the Golem can and does tear the gentile oppressors limb from limb. But to the actors, the Golem is<> a metaphor, for the very act of making theatre at the end of the nineteenth- century is an act of defiance tantamount to the murderous resistance of the sixteenth-century Frankenstein's Monster: "for the first time in a thousand years, a Jew strikes back and gets away with it.''

Or perhaps not. And here's where the question of language comes in. The Yiddish-theatre actors have the courage to be defiant because only we in the audience, as Yiddish speakers, can understand the play's language. But there is another silent audience in the theatre: the Russo-Lithuanian official, there to enforce the anti-Jewish ordinances, who unlike us does not understand Yiddish. Uncle Zeizel (Ray Xifo), when not playing rabbis and Christian judges, intentionally mistranslates the play into Russian, transforming the tragic rage and defiance of Zavel's play into benign farcical comedy.

And so the symbolic resistance of the Mogulesko Troupe succeeds only because it is not understood. And it soon succeeds all too well, when the potency of the theatrical image begins to exceed the mistranslated spoken words used to describe it. The Russian official leaves the audience - possibly out of boredom, or perhaps to return with armed soldiers to arrest them all - forcing us all to consider the possibilities and limitations of resistance, and the possibilities and limitations of theatre as a vehicle for it.

This ingenious premise gives Joselovitz a broad canvas on which to paint his picture of oppression and resistance. The theatrical goings-on are broad and vaudevillian, with pratfalls and sound effects and songs and dances. (You can see how a drama of defiance, so staged, can be mistaken for a light comedy). But at the center of all the mayhem is the heart of darkness: the smoldering emotional pain of Zavel ("a man without a life'' who breathes life to a killing machine), stunningly portrayed by Lloyd; the horrifying description of his wife and unborn child's murder; and the brutality of the Golem's acts of vengeance, a brutality no less vivid and horrifying when staged (by the Mogulesko Troupe, and by Vilna director Lou Jacob) for comedy.

Through all this, Joselovitz explores the nature of violent resistance: how it transforms both the oppressor and the oppressed; how it can supplant the law (the cornerstone of Judaism and, arguably, of civilization) with terror; and whether or not rebellion is worth the price of one innocent victim.

After the intermission, when the return of the absent Russian official is fearfully anticipated, these issues get enacted onstage and debated in the wings. The reverberations and allusions, intended or not - to the Holocaust, to post-Cold-War unilateral disarmament, to the renewed bombardment across the Israeli-Lebanese border - become so thick and dense that they almost threaten to sink the play. And as the play crawls towards its inevitable, inconclusive, and inevitably melodramatic conclusion, it begins to feel as though the playwright, the director, and the able actors (Debora Cahn, TAMIR, Charlie Fersko, and Ben Lipitz, along with the others) are losing control of the material, in much the same way that the Mogulesko Troupe is losing control of their play-within-the-play, and that the Jewish community is losing control of Zavel's Golem.

There have been a few plays in recent years that have shown us theatrical performance in times of social or political duress: the vaudevillians of Peter Barnes's Red Noses singing and dancing their way through the Black Death, and the deported convicts in Australia acting Farquhar at gunpoint in Timberlake Wertenbaker's Our Country's Good, for example.

Vilna's Got a Golem is clearly in this tradition. But unlike Barnes and Wertenbaker, Joselovitz has the courage to show that theatre is not necessarily transcendent and redemptive. Rather, Vilna shows us that making theatre, and even watching it, is as politically potent and as ethically charged as direct action. An art form that, like the Golem-making cobblers in sixteenth-century Vilna, can create life can also take it away. Theatre, like survival, is a matter of life and death.