The debate over the Iraq War resumes in the House this week, with Democrats planning to depart for the August recess on a wave of votes that will underscore their resolve to end U.S. involvement there.

The House is expected to debate the fiscal 2008 Defense appropriations bill as early as Tuesday, when Democrats will introduce a number of Iraq-related amendments, including one that would close down the detention facility at Guantanamo Bay, Cuba, and another that would require minimum levels of training before troops were sent into battle in Iraq and Afghanistan. Other Iraq-related measures are likely to come to the floor as free-standing bills.

The Democrats, however, are still divided over how to write their highest-profile measure, which would attempt once again to set a troop-withdrawal schedule. They hope to find compromise language and vote on it before week’s end.

The raft of Iraq votes is the latest installment of the Democrats’ political strategy, which calls for using floor votes to demonstrate their commitment to bringing U.S. troops home while forcing Republicans to either support them or risk voters’ anger by voting against the measures. With Democrats’ core supporters restless over the party’s role in ending the war and Congress’ standing with the public at historic lows, the political pressure on Democrats is greater than ever. The pre-recess Iraq votes are an opportunity to relieve it, if only temporarily.

“It’s important to do whatever we can before we leave for this break,” said Maurice D. Hinchey, D-N.Y., a war critic. “We have to keep pressing it.”

Party unity is under a strain over the Democrats’ latest troop-withdrawal proposal, by John P. Murtha, D-Pa., the outspoken anti-war chairman of the House Appropriations Defense Subcommittee. His measure would require a pullout to begin 60 days after the measure’s enactment but would not set a deadline for completing it.

A number of liberal Democrats are not happy with Murtha’s amendment because it does not establish a firm deadline for the pullout of U.S. troops.

Lynn Woolsey, Maxine Waters and Barbara Lee, the three liberal Californians who lead the House’s principal anti-war coalitions, plan to meet with Murtha on Monday to discuss the bill. They are said to be considering an alternative to Murtha’s amendment.

“The public doesn’t want us to go backwards,” Woolsey said.

Many anti-war Democrats, however, support Murtha’s proposal. These include Hinchey, Marcy Kaptur of Ohio and Patrick J. Murphy of Pennsylvania.

Moreover, a handful of Republicans are expected to vote for a withdrawal timeline.

“It creates a sense of urgency for a solution to end the brutal violence,” said one such Republican, Wayne T. Gilchrest of Maryland, who has voted before with Democrats on previous withdrawal legislation. “That’s why we’re here. We should be voting on it every day.”

In addition to the meeting between Murtha and liberal anti-war leaders, the entire House Democratic Caucus was expected to meet this week to discuss the amendment. Jan Schakowsky of Illinois, a member of the Democratic whip team, called Murtha’s amendment “a work in progress right now” adding, “There will definitely be A-changes.”

Murtha’s intention in leaving out a completion date was to garner new Republican votes. But it was not clear whether his approach would win them.

“They are attempting to dress it up in all kinds of pretty costumes,” said John M. McHugh, R-N.Y. “But it is all to get us out of Iraq today, precipitously, in whatever way they can.”

C.W. Bill Young of Florida, the ranking Republican on the Defense Appropriations panel, said the GOP was planning to offer several “rather controversial” amendments of its own that have yet to be chosen, including some on Iraq.

Whether or not the withdrawal measure comes to a vote, the House will probably take up several other Iraq-related amendments and possibly stand-alone Iraq bills.

Murtha or James P. Moran, D-Va., will introduce an amendment that would require the closing of the Guantanamo detention center within 180 days and halve the $225 million that President Bush requested for the facility in fiscal 2008. Murtha said he expects it to be adopted.

Murtha may offer another amendment that would require that troops be fully trained and equipped prior to combat deployments. He said such a requirement would cause a de facto drawdown in Iraq.

The other Iraq bills the House could take up include two that the House Armed Services Committee approved July 27. The most contentious would be a measure (HR 3159) by Ellen O. Tauscher, D-Calif., that would require leave time for troops in Iraq equal to their deployment time, although it would allow the president to waive the requirement.

The House may also consider a bill (HR 3087) by John Tanner, D-Tenn., that would require Pentagon reports on war planning.

Alan K. Ota contributed to this story.