Recently opened in London's West End is a musical where the heroine is green. Just about to open at the National Theatre is a musical where the leading female character is black. Caroline, or Change knocks spots off Wicked.
In the latter, the colour that sets apart the future Wicked Witch of the West is used as a symbol of any kind of "difference" that causes the majority to treat its minorities badly. So, in the publicity material, there's a quote from an audience member who sees in the fate of the heroine, the "story of African-American experience in America".
But that perception is questionable because the heroine's skin tone appears to be unique to her, whereas to be black in America is to be part of a community that it would be an insult to treat as a monolith.
As Caroline, or Change acknowledges and dramatises, there are differences of opinion over how to go about effecting change. In the struggle for civil rights, there is not just one approach or attitude. The show is much more thought-provoking and ground-breaking than Wicked. It dares to put a black maid at the centre of an American musical and it does so without sentimentalising.
Set in 1963, in Lake Charles, Louisiana, with a libretto by Tony Kushner, which is through-sung to Jeanine Tesori's music, it tells the partly autobiographical story of the relationship between a little Jewish boy, whose mother has died and whose father has recently remarried, and Caroline, the African-American woman who is employed to do the family's laundry.
"Change" in the title is a pun, denoting both political change and the nickels and dimes that the little boy tends to leave in his pockets, much to the irritation of his New Yorker stepmother. She devises a game whereby she decrees that any loose money that Caroline finds in his pockets is the maid's to keep. It's a well-meant ruse, though perhaps more darkly motivated than the stepmother realises and not exactly calculated to improve long-term relations between the haves and the have-nots, the whites and the blacks.
I caught up with Tony Kushner in a lunch break during rehearsals at the National, where the play's English premiere is directed by George C Wolfe, as it was in New York, and once again stars Tonya Pinkins in the title. The author of the greatest play of the 1990s, Angels in America, and of the recent, highly controversial Steven Spielberg movie Munich, may be the most gifted dramatist of his generation, but he doesn't come on grand. A good deal younger-looking than his 50 years, he is courteous, unassuming and prodigiously articulate, the words tumbling out in a softy spoken cascade.
At the moment Kushner is writing two screenplays: one about his great playwriting forebear Eugene O'Neill, the other is set in the American Civil War, when "black people in the United States were allowed to fight for the union and yet had to wait another hundred years - though the legal foundations for enfranchisement were in place - to be granted full citizenship".
He is also at work on an epic piece for the theatre which looks set to do for the Bush era what Angels in America did for Reaganism.
When Bush visited this country, the Royal Court mounted a reading of one of its fantastical scenes in which, playing on the fact that Laura Bush was once a librarian and is said to have a taste for Dostoevsky, the First Lady reads an excerpt from The Brothers Karamazov and explains the rightness of American foreign policy to a group of Iraqi children who turn out to be ghosts, having perished as collateral damage in her husband's war on terror.
We talk about how Caroline, or Change purposefully overturns expectations. The libretto is dedicated to Maudie Lee Davis, the black woman who worked for the Kushners when Tony was a child. But Caroline has attributes and a disposition that Kushner has invented. "I think that for Americans, the image of a white kid and a black woman in a maid's uniform creates an expectation that's immensely powerful ... that the piece will be a 'mammy story' about a lonely little white kid who's taken care of and raised and helped along by a black woman. And that's precisely what Caroline refuses to do."
And the show does not go in for uplift or easy redemption or offer a facile solution to a complex problem. If there is hope at the end, this comes not (as is usual) from the title character, but from Caroline's young daughter, Emmie, who beckons to a future of principled activism.
Kushner's treatment of money as emotional and political currency is likewise sharp and against the grain of our times. "If there's a lot of money somewhere, that's because there's a scarcity of it somewhere else. Money has a moral meaning. Neo-conservatism has convinced people there's nothing to say about money other than, 'How do you get as much of it as you can?', and, 'How do you keep as much of it as you can away from the government?'"
Kushner was originally going to collaborate with the African-American singer Bobby McFerrin on Caroline, or Change. But he wound up collaborating with white composer Tesori, whose credits include additional songs for the stage adaptation of Thoroughly Modern Millie.
Now there is work to be done finishing his stage epic about the Dubya epoch. Kushner's playing with the idea of having "two versions of Laura Bush battling it out". In a published extract, the First Lady sounds off witheringly at liberal, left-leaning intellectuals: "You guys are just a bunch of mopes. Y'all are just sorrowful types who haven't figured out which sock drawer you ought to shove all your personal misery and disappointment, and, and guilt in...."
It would be a delectable irony if one of the best playwrights in the history of American theatre ends up giving literary immortality to the wife of one of that country's very worst presidents (or rather his hilariously invented version of her). It's to be hoped that Kushner finishes the piece while George Bush is still in office.
Caroline, or Change is at the National Theatre, London SE1 from Wednesday until 4 January. www.nationaltheatre.org.uk; 020-7452 3000