WASHINGTON - Digging in for confrontation, President Bush and Vice President Dick Cheney say they will not budge from sending more troops to Iraq no matter how much Congress opposes it.

"I fully understand they could try to stop me," Bush said of the Democrat-run Congress. "But I've made my decision, and we're going forward."

As the president talked tough in an interview that aired Sunday night, lawmakers pledged to explore ways to stop him.

Democrats remain wary, though, of appearing unsupportive of American troops.

A defiant Cheney, meanwhile, said Democrats offered criticism without credible alternatives. He pointedly reminded lawmakers that Bush is commander in chief.

"You cannot run a war by committee," the vice president said of congressional input.

The aggressive White House reaction came as the House and Senate prepare to vote on resolutions opposing putting additional troops in Iraq.

As the White House watched some GOP support peel away for the plan, it went all-out to regain some footing.

Bush gave his first interview from Camp David, airing Sunday night on CBS' 60 Minutes. It was his second prime-time opportunity in five days to explain why he thinks adding troops can help stabilize Iraq and hasten the time when American soldiers can come home. He addressed the nation from the White House on Wednesday evening.

"Some of my buddies in Texas say, 'You know, let them fight it out. What business is it of ours?' " Bush said of Iraqis. "And that's a temptation that I know a lot of people feel. But if we do not succeed in Iraq, we will leave behind a Middle East which will endanger America."

When asked if he owes the Iraqi people an apology for botching the management of the war, he said, "Not at all."

"We liberated that country from a tyrant," Bush said. "I think the Iraqi people owe the American people a huge debt of gratitude."

Bush announced last week that he will send 21,500 more troops to Iraq to halt violence, mainly around Baghdad, as an essential step toward stabilizing the country's government.

Democrats in Congress, along with some Republicans, were unimpressed and frustrated. Beyond promising to go on record in opposition to the president's approach, the Democratic leadership is considering whether, and how, to cut off funding for additional troops.

"You don't like to micromanage the Defense Department, but we have to, in this case, because they're not paying attention to the public," said Rep. John Murtha, a Pennsylvania Democrat who helps oversee military funding.

It is unclear how any effort by Congress could affect Bush's plan. National Security Adviser Stephen Hadley said the White House has money appropriated by Congress to move the additional forces to Iraq.

Many Democrats favor a phased withdrawal of U.S. troops, along with new diplomatic efforts with Iraq's neighbors.

The Bush administration had hoped that the president's overhauled strategy would lead to some bipartisan unity or that the White House would at least get an extended hearing before legislative leaders made up their minds. Instead, it encountered majority opposition in Congress and by the public.