WASHINGTON — Senate Republicans on Friday blocked a plan by Democrats to pump $56 billion in government spending into the economy through public works projects, help for the jobless and money for states struggling with their Medicaid bills.

The 52-42 tally fell well short of the 60 votes needed to defeat a GOP filibuster. The White House promised a veto anyway, saying the measure would not work and would cost too much.

The House was expected to have better luck with a companion $61 billion House plan later in the day.

The bills follow a bipartisan plan enacted this winter that shipped $600-$1,200 tax rebate checks to most individuals and couples and awarded tax breaks to businesses investing in new plants and equipment.

With the economy still sagging, Democrats have long pressed for a follow-up plan that focused on more spending to extend unemployment benefits, boost food stamp payments and build infrastructure projects like roads, bridges, water and sewer projects and school repairs.

The idea, predictably, got no interest from President Bush and his GOP allies in Congress, and the practical impact of Friday's votes would be to add fodder to the Fall campaign. Several Republicans with tough re-election bids voted for the measure, including Gordon Smith of Oregon, Elizabeth Dole of North Carolina and Norm Coleman of Minnesota broke with their party to embrace the legislation.

"Record spending that could lead to record tax increases or higher deficits will not advance our economic recovery," the White House said in a statement.

The House plan seems more focused on spending that would have an immediate impact on job creation while the Senate measure contains a wish-list of items long-sought by members of the Appropriations Committee, including money to provide U.S. Capitol police with new radios, accelerate NASA's development of a new space vehicle and move the Department of Homeland Security to a new headquarters.

Democrats contend that with the administration insisting on a $700 billion bailout for Wall Street holders of toxic mortgage securities, President Bush should join them in providing federal help to the middle class and the poor. They cited studies by economists that say providing money — through food stamps and unemployment insurance — to people likely to spend it immediately has a proven record of boosting the economy.

"It injects money into infrastructure projects to create jobs directly and generate new economic activities," said Sen. Tom Harkin, D-Iowa. "We get the biggest buck stimulus-wise ... by expanding food stamp benefits. That's the best. The second best, extending unemployment benefits."

"Spending billions of taxpayer dollars on programs and projects that will do little, if anything, to stimulate the economy is simply not the way to dig out of our economic troubles," said California Rep. Jerry Lewis, top Republican on the Appropriations Committee.

Other items in the legislation include:

• Funding for development of advanced batteries for fuel efficient cars.

• Money to upgrade Amtrak rail lines.

• Extending unemployment benefits for the long-term jobless by seven weeks in all states and 13 weeks in states with higher unemployment rates at a cost of $6 billion.

• Temporarily increasing federal payments to states to finance the Medicaid health care program for the poor and disabled. The Senate bill would provide $19.6 billion; the House version would cost $14.7 billion.

Meanwhile, Senate leaders pressed for a vote Saturday on a $630 billion-plus spending bill funding the Pentagon, veterans medical care, homeland security programs and keeping the government other Cabinet agencies running at current levels after the new budget year starts on Wednesday.

That measure also contains $25 billion in federal loans for U.S. automakers to help them retool factories and develop technologies.

The measure, which Bush is expected to sign, also doubles the money for heating subsidies for the poor and provides $23 billion aid plan for disaster-ravaged states. It would avert a shortfall in Pell college aid grants and address problems in the Women, Infants and Children program, which delivers healthy foods to the poor.