American cultural imperialism is fine by John Nathan if it means more Stephen Sondheim musicals

Pacific Overtures, Donmar Warehouse ****

If there's a political point underlying Stephen Sondheim's 1976 musical, it is that in the mid-19th century, Japan was a victim of American imperialism. With 150,000 US troops in Iraq, no doubt there will be those who see fresh significance in Sondheim's theme.

But during Gary Griffin's elegant revival - a production which itself has been imported from Chicago - I found it hard to sympathise with Japan when, in the following century, it indulged in its own brand of more murderous imperialism.

Still, if "Pacific Overtures" proves anything, it is that there is barely a subject on this earth which Sondheim cannot turn into art.

The first half of this simply staged study of Pacific history is an absorbing celebration of a Japanese ritualistic civilisation that revels in isolation. "Blood is flowing somewhere, ideas are growing somewhere... not here" goes one verse of the opening number, the snappily titled "The Advantages of Floating in the Middle of the Sea".

And just as in traditional Kabuki theatre, all the characters, including females, are played by an all-male cast who take on multiple roles. The effect, though, too often gives the show a distracting campness.

Remarkably, this is a musical without a hero. Instead, the narrative is driven by Joseph Anthony Foronda's storytelling Reciter, whom John Weidman's book casts as our guide through the East/West clash of cultures.

But through beautiful and often startingly imaginative - the song "Someone in A Tree" brilliantly splits a witness to the Japanese leadership's first meeting with the American Admiral into a young and old version of the same person - the production's pace in the first act almost stalls to a standstill.

So it's a relief when the second opens with the hilarious and quickfire overtures made by envoys from the world's powers, including a wonderful pastiche of Gilbert and Sullivan. It seems there is no style or subject that is beyond Sondheim's reach.