Senate Democrats said Friday they would soften their marquee measure to withdraw troops from Iraq in a bid to win Republican support, an idea Democratic leaders had rejected just days ago.

The discussions capped a disappointing week for Democrats, who hoped that pressure from the electorate would force enough Republicans in September to side with their efforts to end the war in Iraq. Instead, Republicans frustrated repeated Democratic efforts to force a change in the course of the war.

 On Friday, Democrats once again fell short on their signature plan by Sens. Carl Levin (D-Mich.) and Jack Reed (D-R.I.) to complete the transition of troops from Iraq nine months after enactment of the plan. The plan failed 47–47, short of both the 60 needed for passage and of the 52 it received in July when the Senate voted to end debate on the amendment.

“Obviously the vote is not what we hoped it to be,” said Levin, the Armed Services chairman.

Six senators missed the votes, but some also switched their votes from July. Sens. Ben Nelson (D-Neb.) and Susan Collins (R-Maine) voted against the plan even though they supported the procedural motion in July. Both said they supported ending debate on the amendment, but not the underlying requirements in the plan.

Also, Democratic presidential hopeful Christopher Dodd, a staunch critic of the war, voted against the amendment, signaling that any effort to weaken the Levin-Reed amendment may not pass muster with the liberal wing of the Democratic caucus. The other Democratic presidential candidates — Sens. Hillary Rodham Clinton (N.Y.), Barack Obama (Ill.) and Joseph Biden Jr. (Del.) — voted for the plan on Friday.

 Levin and Reed said after the vote that instead of mandating a hard timeline for withdrawal, they would float the idea of including a goal for withdrawal. They planned to launch a renewed lobbying campaign over the weekend to win GOP support.

Levin said he had a “political inside hunch” more Republicans would be receptive to that plan — but was uncertain whether he and Reed would lose Democrats who support a firm timetable for withdrawal.

Majority Leader Harry Reid (D-Nev.) dismissed the idea of softening that language earlier this week, but on Friday, Levin said he and Reid had lengthy discussions where they agreed to push forward with a goal for withdrawal.

“It’s just a realistic assessment of what the facts are,” Levin said of Reid first appearing to back away from a including goal in the measure to now embracing that notion.

Meanwhile, moderates in the chamber are clamoring for their measures to be considered when the Senate resumes consideration of a defense policy bill next week. Alexander said he and his cosponsor, Sen. Ken Salazar (D-Colo.), would object to unanimous consent requests on the floor next week if their measure is not scheduled for a vote and it appears they have 60 senators in favor of the plan.

“We will object unless we decide Monday that we don’t have a good chance of getting” 60 votes, Alexander said. “Our objective is for our government to speak with one voice.”

The amendment would make the Iraq Study Group recommendations official policy, calling on the government to implement a phased withdrawal of troops with Iraq and engage in direct talks with Iran and Syria.

Reid has called the measure “toothless,” and the White House has expressed reservations even though Defense Secretary Robert Gates was an original member of the commission.