Even as his administration focuses on war, President Bush is struggling to rescue the heart of his domestic agenda from centrist lawmakers who are trying to chop the cost of his tax cut by as much as half.

Moderate senators from both parties are using a budget debate this week to try to slice Bush's 10-year $726 billion proposal to $350 billion. Each party accused the other of trying to get its way under the cover of war, when little attention is focused on the Capitol.

White House officials say they are optimistic about eventually winning approval of most of the economic package that Bush proposed in January, especially if the war in Iraq is swift and he regains the political strength he enjoyed after the November elections.

In the meantime, Commerce Secretary Donald L. Evans and Treasury Secretary John W. Snow are working nearly full-time trying to prevent GOP defections and to woo a few Democrats for the package, which would eliminate the tax on stock dividends and would speed up previously passed rate cuts.

The two Cabinet members, often together and sometimes separately, are holding what they call "listening sessions" in Vice President Cheney's ceremonial office at the Capitol, talking for two and three hours at a stretch as small groups of senators air their worries and objections.

One of the administration's crucial tactical decisions was to market the legislation as a jobs program rather than a tax cut. That is designed to counter claims that the package is unaffordable given the return of deep deficits even before accounting for the cost of war.

"In a $10 trillion economy, to create jobs -- better jobs -- requires an economic package that's got some size to it," Evans said in an interview. "It will benefit stocks, which encourages investment, which leads to jobs creation."

Bush's aides find the struggle somewhat frustrating, since his party controls both houses of Congress. But the moderates' salvo reflects the power that just a few lawmakers can exercise in a Senate where Bush's party has a two-vote majority.

The only Democrat to support Bush's plan so far is Sen. Zell Miller (Ga.), and both sides see the measure as a high-stakes test of party discipline in the closely divided chamber.

A nail-biter vote could come as soon as today, when the Senate may take up an amendment sponsored by the moderates. It would limit the package to $350 billion, which administration officials contend would be too stingy to jump-start the economy.

The measure has two sponsors from each party: Sens. John Breaux (D-La.), Max Baucus (D-Mont.), Olympia J. Snowe (R-Maine) and George V. Voinovich (R-Ohio). Sen. Lincoln D. Chafee (R-R.I.) indicated he was leaning toward joining them. Sen. John McCain (R-Ariz.) has said he opposes tax cuts in wartime but has not endorsed the amendment.

Snowe said deficits must not be a perpetual cycle, and called on senators to "balance the near-term need for tax cuts to help stimulate the economy . . . against the long-term goals of maintaining fiscal responsibility and balancing the budget."

Senate Minority Leader Thomas A. Daschle (D-S.D.) on Tuesday praised "courageous Republicans who have stepped forth, who say that they, under these circumstances, cannot support tax cuts."

The Senate budget resolution being debated this week would set ground rules and procedural protections for the tax legislation when it comes up later this year.

The White House strategy boils down to trying to preserve the package's size and to keep most Republicans on board until after the war, when Bush's aides think Congress will feel political and economic pressure to pass a substantial package.

Snow, who took over for Paul H. O'Neill on Feb. 3, traveled to the Capitol 15 times in his first 30 days on the job and has called lawmakers from Europe and from his car. He said he hopes to "get this done soon," and said he is telling lawmakers the economy is just as much a pillar of American strength as national security is. "We can do both, and I think we have an obligation to do both," he said.

The treasury secretary said the effort to halve the tax cut appears designed to force the administration to choose between the dividend tax cut and the acceleration of the tax cuts Congress passed in 2001.

"I'm spending a lot of time telling people why the elimination of the double taxation of dividends is an essential component of the growth package," he said. "It is also very good for the economy. It will encourage investment." Evans said one of his goals is to "deal with some of their concerns with respect to the deficits and the debt, and talk through how the deficit levels we're talking about are affordable and manageable."

To keep the heat on, White House economic adviser Stephen Friedman plans to travel soon to Maine, the home of two moderate GOP senators, and to Nebraska, home to Democratic Sen. Ben Nelson. Nelson, up for reelection next year in his largely Republican state, is considered a swing vote on many issues.