President Bush signed a bill Friday to pay for military operations in Iraq after a bitter struggle with Democrats in Congress who sought unsuccessfully to tie the money to U.S. troop withdrawals.

Bush signed the bill into law at the Camp David presidential retreat where he is spending part of the Memorial Day weekend. In announcing the signing, White House spokesman Tony Fratto noted that it came 109 days after Bush sent his emergency spending request to Congress.

Bush had rejected an earlier bill because it contained a timetable for withdrawing troops. His signature on this measure, however, doesn't end debate on Capitol Hill over the administration's war policy — a dispute that will heat up again this fall.

"I think the president's policy is going to begin to unravel now," said House Speaker Nancy Pelosi, who expressed disappointment that the bill did not force an end to U.S. participation in the conflict.

Democrats say the drive to bring U.S. troops home is far from over.

"We're going to keep coming back and coming back," said Rep. Rahm Emanuel of Illinois, chairman of the Democratic caucus.

Senate Republican leader Mitch McConnell predicted a change, and said Bush would show the way.

"I think that the handwriting is on the wall that we are going in a different direction in the fall, and I expect the president to lead it," McConnell said. "In other words, I think he, himself, has certainly indicated he's not happy with where we are. And I think we are looking for a new direction in the fall."

The president applauded the bipartisan effort to get an emergency supplemental bill to his desk by the Memorial Day recess.

"This effort shows what can happen when people work together," Bush said after visiting wounded troops earlier at the National Naval Medical Center in Bethesda, Md. "We've got a good bill that didn't have timetables or tell the military how to do its job, but also sent a clear signal to the Iraqis that there's expectations here in America ... about how to move forward."

McConnell also emphasized that the Iraqis need to make progress. "We've given the Iraqi government an opportunity here to have a normal country. And so far, they've been a great disappointment to members of the Senate on both sides," he said.

The war spending bill provides about $95 billion for the wars in Iraq and Afghanistan through Sept. 30 and billions in domestic projects, including more than $6 billion for hurricane relief. The House voted 280-142 Thursday night to pass the bill, followed by an 80-14 vote in the Senate.

Democratic presidential rivals Hillary Rodham Clinton and Barack Obama both voted against the bill.

"I fully support our troops" but the measure "fails to compel the president to give our troops a new strategy in Iraq," said Clinton, D-N.Y.

"Enough is enough," Obama, an Illinois senator, declared, adding that Bush should not get "a blank check to continue down this same, disastrous path."

Their votes continued a shift in position for the two presidential hopefuls, both of whom began the year shunning a deadline for a troop withdrawal.

Sen. John McCain, a GOP presidential contender, said the two Democrats were embracing a "policy of surrender."

"This vote may win favor with MoveOn and liberal primary voters, but it's the equivalent of waving a white flag to Al Qaeda," said McCain, R-Ariz. MoveOn.org is a grass-roots anti-war group that rose to prominence in last year's elections.

Thursday's legislative action capped weeks of negotiations with the White House, which agreed to accept some $17 billion more than Bush had requested as long as there were no restrictions on the military campaign.

In the months ahead, lawmakers will vote repeatedly on whether U.S. troops should stay and whether Bush has the authority to continue the war. The Democratic strategy is intended to ratchet up pressure on the president, as well as on moderate Republicans who have grown tired of defending Bush administration policy in a deeply unpopular war.

The Senate will go first when it considers a defense policy bill authorizing $649 billion in military spending in 2008. The proposed bill, approved this week by the Senate Armed Services Committee, cut $12 billion from the administration's $142 billion war-related request to fund other programs, including an increase in the size of the Army and the Marine Corps.

The most critical votes on the war are expected to be cast in September, when the House and Senate debate war funding for 2008. The September votes probably will come after Iraq war commander Gen. David Petraeus tells Congress whether Bush's troop buildup plan is working. Also due by September is an independent assessment of progress made by the Iraqi government.

The U.S. has spent more than $300 billion on Iraq military operations so far, according to the congressional Government Accountability Office.