WASHINGTON - With the Senate poised today to restrict President Bush's ability to conduct the war in Iraq, the White House and Congress are moving toward their biggest policy confrontation in more than a decade.

The last time the capital witnessed this kind of head-on policy collision between the branches of government was in 1994, when a newly elected Republican Congress took aim at a Democratic president and eventually forced the shutdown of the federal government. This time, a newly elected Democratic Congress is taking on a Republican president in an effort to force a drawdown to an increasingly unpopular war.

At the moment, neither side has much incentive to compromise, because the war is a signature issue for both. Bush has wagered his legacy on the outcome of his decision to invade Iraq, and Democrats owe their control of Congress to voters angered by the war's deepening losses.

"I don't think either one can afford to back down, and that leads to the inevitable," said David Gergen, a veteran political strategist who has served as a top adviser to presidents of both parties.

The inevitable is a long-threatened presidential veto of a bill that would provide funds for the war but would also lay out a timetable for withdrawal.

When it comes, Bush's veto is expected to leave the two sides accusing each other of perfidy: The president will accuse Congress of cutting off funds for troops in the middle of the battlefield, and Democratic leaders in Congress will accuse Bush of stubbornly ignoring the will of the American people, the true needs of the troops, and the raw power of common sense.

Also likely is a scenario that drags the confrontation out for months, probably through the summer, with each trying to fix blame for the stalemate on the other.

The two sides are drawing those battle lines now, and it was evident in their rhetoric yesterday.

Speaking to the National Cattlemen's Beef Association, Bush called on members of Congress to "stop making political statements and start providing vital funds for our troops."

"Some of them believe that, by delaying funding for our troops, they can force me to accept restrictions on our commanders that I believe would make withdrawal and defeat more likely. That's not going to happen," Bush said. "If Congress fails to pass a bill to fund our troops on the front lines, the American people will know who to hold responsible."

For their part, Democratic leaders sent a letter to Bush suggesting he is the one being unreasonable.

"Mr. President, this is the time to sit down and work together on behalf of the American people and our troops," House Speaker Nancy Pelosi (D., Calif.) and Senate Majority Leader Harry Reid (D., Nev.) wrote. "We stand ready to work with you, but your threats to veto a bill that has not even been presented to you indicate that you may not be ready to work with us."

And Pelosi said at a news conference: "Calm down with the threats. There's a new Congress in town. We respect your constitutional role. We want you to respect ours."

If neither side seems in a hurry to reach a resolution, one reason is that both have more time on their side than their rhetoric would suggest. Although Pentagon officials have said publicly that funds for the troops will start running out in mid-April, they also have acknowledged that troops now in the field will not be affected for several more months.

Defense Secretary Robert Gates has said that a cutoff in funding would mostly affect replacement brigades, and most of them are not scheduled to be deployed until next fall.

Norman Ornstein, who studies relations between Congress and the White House at the American Enterprise Institute, said that the confrontation "will play out over months, no matter what," and that the "crunch probably won't come until August."

"If you get a confrontation over an emergency [spending bill], presidents almost always win those," Ornstein said. "He has the bully pulpit of saying, 'They're trying to tie my hands, blackmail me, and cut off funds.' "

Moreover, refusing to compromise also would buy the president more time for his surge strategy to show benefits on the ground in Iraq. "The odds of that are very slim, but they are not zero," Ornstein said.

If the scenario plays out as expected, the Senate will vote as early as today to adopt an emergency war-spending bill that requires a troop withdrawal to begin within 120 days, and sets a goal of March 31, 2008, for its completion. The House-approved bill mandates withdrawal for nearly all combat troops by the end of August 2008. Next, Senate and House negotiators will draw up a compromise bill.

When that compromise arrives, probably shortly after Congress returns from its spring recess in mid-April, Bush is expected to veto it.

At that point, each will try blame the other. How successful they are then may depend in large part on how the confrontation is framed now in the public mind.

"Both sides have an interest in gaining the upper rhetorical hand with the public," Gergen said. "Bush wants to paint [the Senate bill] as an avenue to defeat, and the Democrats say the opposite." The Democrats argue that Bush "is not accepting any limitations or boundaries on the war."

One tool the Democrats could use would be to pass temporary spending extensions, known as continuing resolutions, for 30 days or so at a time. That would enable them to avoid the charge that they have cut off funding for the troops while keeping the heat on the White House to compromise.

But in the end, the confrontation may well wind up as a test of wills. Bush cherishes his reputation as a resolute leader who is willing to buck public opinion when principle is at stake. Congress is led by pugnacious Democrats who chafed for years in the minority, under what was generally seen as a highly partisan and heavyhanded Republican majority serving a recalcitrant president.

If the confrontation continues through the year, Bush may take more of the blame, Ornstein said. But since his standing with the public is already so low, the president may be willing to take that risk, because he actually has less to lose with the public than congressional leaders do.

"In the long run, we've had four years of the war," Ornstein said, noting recent polls show two out of three Americans favor setting a timetable for withdrawal. "With a supermajority sentiment that this was a disaster, Bush is going to suffer for it."

Senate, House Bills Compared

The Senate debated a war- spending bill yesterday that would, among other things:

Provide $122 billion, including $96 billion to the Defense Department, mostly to fight the wars in Iraq and Afghanistan, and $20 billion for domestic spending.

Require the president to begin pulling an unspecified number of combat troops out of Iraq within 120 days of the bill's enactment, with the nonbinding goal of completing the redeployment by March 31, 2008.

Allow for some troops to be left behind to conduct counterterrorism missions and train Iraqi forces.

Call on Iraq's government to enact a plan to equally share oil revenues, disarming the militias, amending the Iraqi constitution, and deploying trained forces

to stabilize Baghdad.

Add $161 million to

protect against pandemic flu, $1.3 billion for defense health programs, and

$4 billion for agricultural aid.

Increase the minimum wage and cut some related small-business taxes.

Bar funds from being used to close Walter Reed Army Medical Center unless the defense secretary certifies there will be no disruption

in patient care.

The House-passed

war-spending bill would:

Provide $124 billion in emergency spending, including $96 billion to Defense and $20 billion for domestic projects.

Require the president to begin pulling combat troops out of Iraq by March 2008, completing the redeployment within 180 days.

Require the president to begin pulling troops out as early as this July 1 if he cannot certify that the Iraqis are making progress on meeting benchmarks to reduce the nation's violence.

Allow for some troops to be left behind to conduct counterterrorism missions and train Iraqi forces.

Add $1 billion to the president's request to protect against pandemic flu,

$1.7 billion for defense health programs, and

$4 billion for agricultural aid.

Increase the minimum wage and cut some related small-business taxes.

Provide $74 million for peanut storage and

$25 million for spinach growers.

Bar funds from being

used to close Walter Reed.

SOURCE: Associated Press