WASHINGTON-Leaders in both parties cheered President Bush last night for what they called a strong and measured message on Iraq in his State of the Union address, even as Democrats attacked him bitterly for domestic policies they said were wrong-headed.

Republicans met Bush with an exuberant roar as he took the podium in a packed House chamber shortly after 9 o'clock last night, while more skeptical Democrats gave him respectful applause.

Those responses held later in the evening after the speech, as Bush's Republican allies rallied strongly behind both his international and domestic proposals, and Democrats carefully raised questions about going to war with Iraq while opposing him at nearly every turn on his economic and health care proposals.

"The president challenged us to enact an agenda as ambitious as this nation is great," said Senate Majority Leader Bill Frist, a Tennessee Republican.

Rep. Steny H. Hoyer, a Southern Maryland Democrat who is his party's No. 2 House leader, said Bush's comments on Iraq "were extremely important" in making the case to the American people for a war to disarm Saddam Hussein, and Hoyer praised his decision to go to the United Nations on Feb. 5 to consult with members on how to proceed.

"I share the view that Hussein has not complied with countless U.N. resolutions, and we must decide in concert with our allies how to address this menace," Hoyer said.

But he also called Bush's economic plan "deja 'voodoo economics' all over again," joining other Democratic leaders in arguing that the president's rhetoric on pressing domestic issues did not match his actions.

"There's a huge gap here between the rhetoric and the reality on the economy," said Sen. Paul S. Sarbanes, a Maryland Democrat.

Although some Democrats supported Bush's stance on Iraq, many continued to voice lingering worries, saying the president should focus on the war on terrorism instead of going after Saddam Hussein.

"Last year, the president said the war on terrorism was the most important thing. This year, he's got a new war. Well, I think we haven't ended the other war," said Sen. Barbara A. Mikulski, a Maryland Democrat.

Republicans, too, raised concerns about Bush's Iraq policy.

Rep. Roscoe G. Bartlett of Western Maryland said Bush made a strong case, but Bartlett voiced "grave concerns" about the United States unilaterally attacking Iraq.

"I hope that I can be as fond of [Bush's] Iraq policy as I am of him, and I will sleep well tonight with the hope that he will act wisely with the counsel of all of his advisers," said Bartlett, a member of the Armed Services Committee.

But some prominent Republicans who have criticized Bush's approach on Iraq said he allayed their fears.

"He didn't declare war tonight, he didn't say we're not going to the U.N., he didn't minimize or marginalize the inspectors," said Sen. Chuck Hagel, a Nebraska Republican who has been critical of Bush's Iraq policy. "It showed maturity in this speech, and good judgment."

Some senior Republicans whose support Bush needs to push his domestic agenda through Congress have, however, raised grave concerns about some marquee points Bush touched on in his speech, including portions of his economic plan and his sweeping proposal for Medicare reform.

Sen. Charles E. Grassley of Iowa, the chairman of the Finance Committee, said he opposes Bush's plan to provide a prescription drug benefit under Medicare - the government health program for the elderly - by requiring that seniors join a private managed care plan.

Seniors "tend to have a great deal of cynicism about government, and they're going to be very, very nervous if you talk about that they have to do something else if they want prescription drugs," Grassley said. "I don't want them to have to go into a new [health plan] just to get prescription drugs."

At the same time, some Republicans have expressed doubts about the centerpiece of Bush's economic growth plan: a $374 billion plan to eliminate the tax that shareholders pay on corporate dividends.

Rep. Bill Thomas of California, the chairman of the tax-writing Ways and Means Committee, told reporters Monday that he is concerned the dividend proposal could have unintended consequences in the securities markets.

Still, reaction to the speech fell, for the most part, along predictably partisan lines. Republicans said Bush laid out clear, concise and convincing arguments on the pressing issues of the day - the case for going to war with Iraq, for reforming Medicare and for a deep tax cut to spur economic growth - while Democrats said his proposals would not solve the nation's problems.

Sen. Don Nickles, the Oklahoma Republican who chairs the Budget Committee, heaped praise on Bush's economic plan: "These are very positive, very pro-growth, pro-family changes that he is saying that we can help make our economy grow better and help American families in the meantime. So I'm excited about that proposal."

Minority Leader Tom Daschle and House Minority Leader Nancy Pelosi of California broadened their criticism in a joint appearance Monday in Washington where they pre-empted Bush's speech with challenges to his approaches to the crises in Iraq and North Korea, as well as his domestic plans.

Democrats assembled charts, statistics and quotes to back up their assertion that Bush has paid lip service to popular priorities, such as education and homeland security, while squandering the resources needed to pay for them on a large tax cut.

Daschle said last night that Bush "passed up this opportunity to close the widening credibility gap that is putting him further and further out of touch with the American people.