Yet Republicans seemed to have the votes to erect a procedural roadblock to stop a Democratic plan that is backed by a majority of the Senate to withdraw U.S. combat troops by the end of April 2008.
A showdown vote on the plan was expected shortly before noon EDT( 1600 GMT) on Wednesday by weary and sharply divided lawmakers.
"Republicans will need to choose whether they want to protect the president or protect our troops," said Senate Democratic Leader Harry Reid of Nevada.
Democrats repeatedly noted that more than 3,600 U.S. soldiers have died in the increasingly violent Iraq war, now in its fifth year, while Republicans warned a troop pullout would embolden terrorists and increase the risk of attack on the United States.
Senate Republican Leader Mitch McConnell of Kentucky fired back: "The Democrats, unfortunately, are trying to undermine the efforts of our troops and restrict the ability of our generals to carry out their mission."
Republicans denounced the all-night debate as a stunt by Democrats who have drawn fire from voters for failing to deliver on a 2006 campaign vow to withdraw troops.
Outside the Capitol, a couple dozen protesters chanted, "Lead us out of Iraq now, Nancy," to House of Representatives Speaker Nancy Pelosi, after the California Democrat held a news conference on an unrelated topic.
In preparation for the all-night session, portable beds were set up in a room near the Senate. Pillows, snacks and toothbrushes were also brought in.
Democrats control the Senate 51-49 but have been unable to prevail because 60 votes are needed to clear the way for a vote on passage of the measure offered by Senate Armed Services Committee Chairman Carl Levin, a Michigan Democrat.
Under the legislation, an unspecified number of noncombat U.S. troops would stay in Iraq after the withdrawal to help train Iraqi soldiers, conduct counter-terrorism missions and protect U.S. diplomats.
The White House has been urging Democrats and wavering Republicans to hold off on even considering troop withdrawals until mid-September when the Pentagon will deliver to Congress a status report on Bush's attempt to secure Baghdad by injecting about 30,000 more soldiers.
But Iraq's ambassador to the United States, Samir Sumaidaie, said even more time may be needed.
"I think September is frankly too soon to show anything more than an inkling of its potential but yes, we want that (the surge) to continue until we see real fruit," the ambassador told reporters at the Iraqi embassy.
Sen. Joseph Lieberman of Connecticut, a former Democrat who turned independent because of his staunch backing for the war, ripped into lawmakers pushing to bring combat troops home before their mission is completed.
"To me the sad truth is that too many of our colleagues in the chamber are already asleep when it comes to Iraq," Lieberman told a news conference while cots were carted into the Capitol. "They're already asleep about the stakes America faces in Iraq."
Five hours into the often stormy debate, lawmakers managed to come together briefly to overwhelmingly pass a Republican measure that states it was in the U.S. interest that Iraq not become a failed state and a safe haven for terrorists.
With a parade of speeches by senators along with a planned candlelight vigil across the street by anti-war groups, opponents vow to increase the drum beat of opposition to the war even as Republicans defended Bush's policies.
Güncelleme Tarihi: 18 Temmuz 2007, 00:45