Washington ? Democrats now running Congress will not give President Bush a blank check to wage war in Iraq, House Speaker Nancy Pelosi said Sunday, suggesting they could deny him the money should he call for additional troops.

Yet Pelosi’s second-in-command and a Senate leader on foreign affairs questioned the wisdom and legality of using the power of the purse to thwart the White House as Bush prepared to announce his revised war strategy this week – perhaps on Wednesday.

Republicans, now in the minority, said more troops were needed to get a handle on the spiraling violence in Iraq. They also cast doubt whether Democrats would – or could – block the president’s plans. “Congress is incapable of micromanaging the tactics in the war,” said Senate Minority Leader Mitch McConnell, R-Ky.

Pelosi made clear that her party supported boosting the overall size of the military “to protect the American people against any threats to our interests, wherever they may occur. That’s different, though, from adding troops to Iraq.” She also said Democrats would not cut off money for those troops already in Iraq.

But dollars for a further buildup in Iraq – Bush’s expected plan could send as many as 20,000 additional U.S. troops – will get the strictest of scrutiny, she said.

“The burden is on the president to justify any additional resources for a mission,” said Pelosi, D-Calif. “Congress is ready to use its constitutional authority of oversight to question what is the justification for this spending, what are the results we are receiving.”

“There’s not a carte blanche, a blank check for him to do whatever he wishes there,” she added in an interview taped Saturday and broadcast Sunday.

Asked about Pelosi’s remarks, White House spokesman Alex Conant said Bush welcomed any ideas on Iraq that “lead to success.”

“We’re glad the speaker wants us to succeed in Iraq,” he said.

Bush was putting the finishing touches on his new policy over the weekend. In addition to the troop increase, it could provide more money for jobs and reconstruction programs in Iraq.

Since the attacks of Sept. 11, 2001, Congress has approved about $500 billion for Iraq, Afghanistan and other terrorism-fighting efforts. The White House is working on its largest-ever appeal for more war funds – a record $100 billion, at least. It will be submitted along with Bush’s Feb. 5 budget.

While leading Democrats reaffirmed their opposition to a troop buildup, several did not join Pelosi in suggesting it was possible Congress could deny Bush the money for the additional forces.

“I don’t want to anticipate that,” said House Majority Leader Steny Hoyer, D-Md.

Sen. Joe Biden, chairman of the Senate Foreign Relations Committee and a 2008 presidential candidate, said increasing troops would be a “tragic mistake.” But he contended Congress was constitutionally powerless to second-guess Bush’s military strategy because lawmakers had voted to authorize the commander in chief to wage war.

“As a practical matter, there’s no way to say, ‘Mr. President, stop,'” Biden said, unless enough congressional Republicans join Democrats in persuading Bush that the strategy is wrong. “You can’t go in and, like a tinker toy, and play around and say, ‘You can’t spend the money on this piece and this piece.'”