President Bush fulfilled a major promise of his campaign for president yesterday, signing into law the most sweeping tax cut in two decades, which he called "the first major achievement of a new era."

Bush signed the $1.35 trillion tax cut -- which includes soon-to-be-mailed rebate checks of up to $600 -- amid the kind of presidential pomp he usually disdains: a formal ceremony in the East Room, with a Marine band playing "Hail to the Chief."

For Bush, the moment was the first major victory of his first year in office and the vindication of a political strategy that appeared dubious in the campaign and politically improbable even after he narrowly won the election. But his own relentless salesmanship around the country, and an economic slowdown that he turned into a justification for economic stimulus, turned the idea into an inevitability.