WASHINGTON (CNN) -- The House of Representatives approved another $70 billion in war spending on Wednesday, capping a year of frustration for Democrats who took control of Congress on pledges to end the war in Iraq.

Senate Majority Leader Harry Reid says President Bush is driving allies "over the cliff."

The money was part of a $555 billion measure that funds government agencies for the 2008 budget year. It passed on a 272-142 vote, more than a month after Democratic leaders had refused to approve more money for Iraq without requiring President Bush to begin withdrawing U.S. combat troops from the nearly five-year-old conflict.

Democrats credit their opposition to the widely unpopular war for the 2006 election victories that brought them to power in both houses of Congress.

But their efforts to end the war have foundered all year in the Senate, where Bush's Republican allies have successfully used filibusters to kill them.

Senate Majority Leader Harry Reid, Democrat from Nevada, said Democrats would continue trying to bring an end to the conflict, and he warned that Bush was driving his GOP allies "over the cliff" by continuing the war.

"I hope this last year of his eight-year reign will be one where he will understand -- and more importantly, the Republican senators will understand -- that they've got to break away from this," Reid said.

Rep. David Obey, the chairman of the House Appropriations Committee, said Democrats "have tried every way known to man to bring this war to a conclusion."

"I think it is clear that if the nation wants a change in direction with respect to this war, it has only two options," said Obey, D-Wisconsin. "One is to elect more progressive voices in the United States Senate, and second is to elect a president who has a different set of priorities domestically and a different vision for America's involvement in the Middle East -- and especially in Iraq."

Most Republicans repeatedly refused to break with the president. They pointed to reports of declining U.S. military and Iraqi civilian casualties since August as a sign that Bush's commitment of nearly 30,000 additional troops to Baghdad and its surrounding province was bearing fruit.

"It's an undeniable fact -- or, should I say, an inconvenient truth -- that things are getting better in Iraq, and I think the American people are noticing," Senate Minority Leader Mitch McConnell, a Kentucky Republican, said Wednesday.

"I'm not saying that we're totally out of the woods. I don't think they believe that," he said. "But I think the American people are aware that things have improved, and most Americans are not pulling for us to lose."

Months of upbeat reports from U.S. commanders in Baghdad have failed to improve U.S. public opinion about the war. A CNN-Opinion Research Corp. poll taken December 6-9 found support for the conflict at 31 percent, with 68 percent expressing opposition -- and 69 percent favored withdrawing some or all American troops from Iraq.

The Bush administration has requested about $200 billion in war spending for 2008. Most of the money would go to Iraq, which the Pentagon says is costing about $2 billion a week.

The House had approved about $50 billion of that in November, but with demands that the president begin withdrawing troops from Iraq within 30 days.

The White House called that unacceptable, and Pentagon officials warned they would have to shutter U.S. bases and begin laying off as many as 200,000 civilian employees and contractors by March without the funds.

The provision calling for an American pullout stalled in the Senate, which killed two other efforts by Senate Democrats on Tuesday night that would have tied war funding to a plan to withdraw U.S. troops from Iraq. E-mail to a friend

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