The news that the economy had expanded at a 7.2 percent annual rate — the best performance since 1984 — gave Mr. Bush and his party a compelling piece of evidence to back their assertions that they have put the nation back on the road to prosperity a year before Election Day.

"The president's policy, as I see it, props up the economy in the short-term, but the growth of deficits and debt under his plan undermines economic growth in the long-term," said Senator Kent Conrad, Democrat of North Dakota. "It's a little like a drunk going on a binge. It feels good for awhile, but you all know the hangover is coming."