Mirror, mirror on the wall, who is the greenest of them all? There was a whiff of fairy tale to the spectacle of the globe's two biggest automakers preening over their environmental images last week. For decades, General Motors and the Ford Motor Co. have publicly resisted attempts to tighten fuel economy and clean up toxic tailpipes. All the while, they have outdone one another in launching ever more gas-guzzling behemoths. Yet there they were, suddenly jostling each other over which could produce more fuel-efficient vehicles.
At a hastily called news conference outside Detroit, GM's pugnacious vice chairman Harry Pearce pronounced...