President Bush urged the Senate Thursday to approve a compromise $2.4 trillion budget for 2005, but unwavering defiance by the chamber's moderate Republicans made passage seem virtually impossible.  

A day after the GOP-led House approved the fiscal plan by 216-213, top Senate Republicans acknowledged they had yet to unearth the two additional votes they need to prevail. With Congress set to start a week-long Memorial Day break on Friday, Senate Majority Leader Bill Frist (search), R-Tenn., said he had not decided whether to even begin debate.

Four moderate GOP senators — and moderate Sen. Ben Nelson (search), D-Neb., seen as a potential supporter — have expressed opposition to the plan because it lacks tax-cut curbs they say are merited by massive federal deficits.

The budget would increase defense and anti-terror spending and hold most domestic programs level. It would also deliver a fraction of the tax cuts Bush wants — along with a near-record $367 billion deficit.

In a private visit with Republicans and a subsequent written statement, Bush tried intensifying the pressure by imploring the narrowly divided Senate to pass the fiscal blueprint. House-Senate bargainers completed the compromise this week after a two-month standoff.

The budget "meets our nation's highest priorities of winning the war on terror, protecting the homeland, and helping our economy continue to create new jobs," Bush said in his statement.

"I urge the Senate to follow the House's lead and pass this budget so that we can continue making progress on our shared agenda of building a safer, stronger, and better America," he said.

An election-year budget stalemate between the two Republican-led chambers would belie earlier statements by party leaders that they would complete the plan on time — last April 15 — to show how well they can govern.

The budget sets guidelines for future tax and spending legislation and does not need the president's signature. Lawmakers can work on those later measures without a budget, but they would lack its procedural advantages that would make those bills easier to pass.

Bush's relatively gentle cajoling contrasted with bristly statements this week that House GOP leaders have made about the maverick Senate moderates.

House Speaker Dennis Hastert (search), R-Ill., asked reporters if holdout Sen. John McCain (search), R-Ariz., is a Republican. And House Majority Leader Tom DeLay, R-Texas, said the moderates "need to read the Republican philosophy" of cutting taxes.

Unyielding after weeks of lobbying, they seemed no more willing to reconsider after the barrages by the House leaders.

"What the speaker said was tremendously unhelpful," said Sen. Lindsay Graham, R-S.C., who is not among the four.

Besides McCain, the other recalcitrant senators were Olympia Snowe and Susan Collins, both R-Maine, and Lincoln Chafee, R-R.I.

The moderates favor requiring any tax cuts or benefit increases over the next five years that worsen the deficit to be paid for with tax increases or spending cuts. Sixty of the 100 senators would be allowed to vote to ignore the restriction.

The compromise budget imposes that restriction only through next April 15, and exempts the only tax bill likely to become law during that period.

The budget would:

— Allow $55 billion in tax cuts next year, though only half are likely to become law because they would be exempted from Senate stalling tactics. Bush proposed $1.3 trillion in 10-year tax cuts;

— Provide the $421 billion Bush wants for defense, 7 percent over this year. There is another $50 billion for wars in Iraq and Afghanistan, of which Bush has so far requested half;

— Increase domestic security by 15 percent to $31 billion, while holding remaining domestic programs to $369 billion, $2 billion over this year.