WASHINGTON, May 15 (UPI) -- The veto of the 2007 war supplemental -- and the troop-withdrawal language contained within it -- has not ended the U.S. Congress' attempts to limit the war.

Top Senate Democrats this week introduced two more amendments to impose timelines on the withdrawal of troops and benchmarks for the Iraqi government to meet.

Sens. Carl Levin, D-Mich., and Harry Reid, D-Nev., have offered an amendment to the Water Resources Development Act to begin the withdrawal of American troops from Iraq by October 1, 2007, if certain commitments are not met by the Iraqi government.

The withdrawal would have to be completed within six months, the same terms that drew a presidential veto when they were made part of the 2007 supplemental war spending bill.

However, this version of the language provides for a presidential waiver, a concession Levin believes will obviate any White House threat to veto the bill.

The benchmarks the Iraqi government must meet include: enacting a broadly accepted hydrocarbon law that equitably shares oil revenues among all Iraqis; adopting legislation providing for provincial and local elections; reforming de-Baathification laws; amending the national constitution; spending $10 billion in Iraqi funds on reconstruction; reducing sectarian violence; and Iraqi battalions becoming more independent of U.S. support.

If those conditions are not met -- and monthly reports to Congress would be provided to track their progress -- U.S. troops would begin to be withdrawn from Iraq over the following six months.

"By providing for the presidential waiver, we are removing any reason for the president to veto the supplemental funding bill," Levin stated Monday.

Reid and Sen. Russell Feingold, D-Wis., have also introduced an amendment that would call for the withdrawal of U.S. troops beginning 120 days after enactment, and completed by March 2008, without condition or presidential waiver.

Both amendments are expected to be voted on this week.