DETROIT — The government's "cash-for-clunkers" program drew car and truck buyers back to American showrooms last month, making July the best month for auto sales in nearly a year and offering powerful evidence that the rebates were working as senators debate whether to continue them.

In fact, some automakers, dealers and government officials declared an end to the industry slump that nearly claimed the lives of General Motors and Chrysler.

"We certainly expect that we've seen the worst of it," said Dave Zuchowski, Hyundai Motor's vice president of U.S. sales, whose sales rose 12 percent over July of last year, the second-best in the industry, behind only Suzuki.

Even though the overall U.S. market fell 12 percent when compared with July of last year, gleeful automakers reported vastly better sales than in the dismal first half of 2009.

In Washington, the White House urged the Senate to approve $2 billion without delay or risk ending the big rebates for car buyers by week's end.

Buyer demand was so strong that the government had nearly spent in one week the $1 billion that Congress had expected to last until Nov. 1.

"I think probably this is the greatest one-week energy conservation program that may have come out of Washington or anywhere else," said George Pipas, Ford's top sales analyst.

Without the clunkers program, July sales probably would have been about the same as June, Pipas said.

Democrats remained concerned about lining up enough support for the incentives, which offer up to $4,500 per vehicle.

The House approved the rebates last week before heading home for the August recess.