When it comes to rock 'n' roll, Luke Doucet and Melissa McClelland have a commitment problem. They can't come to terms with the fact that they are rockers. This identity crisis should be evident to anybody who has heard Whitehorse's excellent second album, The Fate of the World Depends on This Kiss. The two-thirds of the album that are down 'n' dirty angular blues rock is fantastic, making the remaining one-third devoted to pretty Americana seem extraneous. In their solo work, the married Canadians have shown a fondness for singer/songwriter introspection. But as a duo, they're at their best when they sing against the sad chime of an electric guitar and the rhythm of a saloon piano. Fortunately, even at their most introspective, Doucet and McClelland's vocals sparkle. But when they rock ("Achilles' Desire," "Devil's Got a Gun," "Jane"), their voices sizzle.