It is Fall 1936. Steel strikes and labor riots are in the news, and actors are lining up for WPA jobs, just like everyone else. Olive Stanton (Emily Watson), who has been singing songs on the streets for a nickel apiece and washing up at open fire hydrants, gets a lucky break in the Federal Theater Project: a job as a stagehand for what looks to be (we don't see much more than part of a rehearsal) a fantastical and frightening version of Faustus, directed by Orson Welles (Angus MacFadyen: Braveheart). Songwriter and playwright Marc Blitzstein (Hank Azaria: Mystery, Alaska; Mystery Men) is writing the musical that will be this federal theater group's next production: Cradle Will Rock, in which angry workers bring about the downfall of an industrial magnate. "It will piss off all the right people," Orson says with glee.

Olive got her break thanks to Hazel Huffman (Joan Cusack: Toy Story 2, Arlington Road), a clerk at the jobs office who took pity on her. Hazel has some beefs with the Federal Theater Project, though. Aghast at what she see as snobbery and elitism in the project, she has organized a protest group, through which she meets Tommy Crickshaw (Bill Murray: Rushmore), a vaudevillian ventriloquist who can't see that he is a relic of a bygone age. Hazel ends up testifying at Congressional hearings into the project, though that body is more worried that federal theater is full of communists. Hallie Flanagan (Cherry Jones), the head of the project, finds herself defending a children's play the project produced: Is Revolt of the Beavers teaching kids Marxism and trying to incite class warfare? Congress wants to know.

Marc's hallucinatory muses (he hasn't slept in a while) prompt him to remember, as he's writing a song for a prostitute at the heart of Cradle Will Rock, who the real whores are -- police, industrialists, artists, anyone who takes money in exchange for his soul. Meanwhile, steel tycoon Gray Mathers (Philip Baker Hall: The Insider, Magnolia) is taking advantage of the conflict in Europe by selling to his company's wares to Italy. Mathers and Nelson Rockefeller (John Cusack: Being John Malkovich, This Is My Father) hang out with Mussolini's "cultural emissary," Margherita Sarfatti (Susan Sarandon: Stepmom) -- she helps them buy up some of Italy's greatest works of art, so they can hoard it for themselves. And Rockefeller is contracting with the painter Diego Rivera (Rubén Blades: The Devil's Own) to create a mural for his new project, Rockefeller Center, but only if Diego makes a pleasant, colorful picture. Diego, however, believes that "nothing in art is inappropriate," which will cause some problems with his patron.

Cradle Will Rock, the play, asks the question, Where do we draw the line between the need to safeguard our integrity and the need to feed and clothe ourselves? And this question is something Cradle Will Rock, the film, keeps coming back to. If there's a local villain in this federal theater group, it is the actor John Adair (Jamey Sheridan: The Ice Storm), with his insistence on sticking to union work rules, even when it means calling for a break in the middle of an important moment during a rehearsal. John inspires a mesmerizing rant from Orson Welles, his director, about theater "atheists" who are not artists but mere "workers." John proves himself a theater atheist again later, not the least evidence of which is when he forces Olive to decide where to draw the line for herself. Another actor, Aldo Silvano (John Turturro), also must decide how high a moral price he's willing to pay to keep a roof over the heads of his wife and young children. And the entire federal theater group will have to choose what's important to them when Congress shuts down their production of Cradle Will Rock.

Long takes in which characters from the parallel stories cross paths shift us from one plotline to another, and Robbins juggles all his people and places with aplomb. As enjoyable and provocative as the story is, though, what really makes Cradle Will Rock worth catching is the fabulous ensemble cast. There are no big star turns -- instead, every single member of the large and impressive cast seems to take his or her relatively small role and run with it, like they were all hungry and desperate Federal Theater Project actors. Cradle Will Rock positively bubbles over with enthusiasm, as if Robbins and a bunch of his really talented friends all got together and said, "Gosh darn it, let's make a movie!" Particularly impressive are the usually sleek Cary Elwes (Liar Liar), who looks as if he put on 50 pounds for his spot-on impersonation of federal theater producer John Houseman, and Vanessa Redgrave (Deep Impact, Wilde) as the Countess LaGrange (and Gray Mathers's wife), goofily delirious theater hanger-on and patron.

Defiant and powerful, Cradle Will Rock is not just a historical piece but a cautionary tale for the next century. We're swinging back into a more restrictive era: the rise of ratings systems for everything from video games to TV shows is only the beginning. Cradle Will Rock reminds us of the necessary function that artists serve: As our fools and court jesters, they not only entertain but can (and should) comment on the action in the throne room. Artists need the freedom to bop the king on the head, figuratively speaking, when he needs it. The final shot of Cradle Will Rock serves as a haunting condemnation of theater today and as a warning that that freedom is slipping away.