Here is an explanation of the proposal (NY Times):
Following is the 50-to-48 roll-call vote in the Senate on Thursday by which Republicans turned back Democratic a resolution to require a United States troop withdrawal from Iraq to begin within 120 days. The 48 votes were 12 short of the 60 needed for passage. A “yes” vote was a vote to support the measure. Voting “yes” were 46 Democrats, 1 Republican and 1 independent. Voting “no” were 2 Democrats, 1 independent and 47 Republicans. Two senators did not vote.
If your senator is on this list, call his/her office and give them a piece of your mind:
Dems: Nelson, Neb.; Pryor, Ark.
Repubs: Alexander, Tenn.; Allard, Colo.; Bennett, Utah; Bond, Mo.; Brownback, Kan.; Bunning, Ky.; Burr, N.C.; Chambliss, Ga.; Coburn, Okla.; Cochran, Miss.; Coleman, Minn.; Collins, Me.; Corker, Tenn.; Cornyn, Tex.; Craig, Idaho; Crapo, Idaho; DeMint, S.C.; Dole, N.C.; Domenici, N.M.; Ensign, Nev.; Enzi, Wyo.; Graham, S.C.; Grassley, Iowa; Gregg, N.H.; Hagel, Neb.; Hatch, Utah; Hutchison, Tex.; Inhofe, Okla.; Isakson, Ga.; Kyl, Ariz.; Martinez, Fla.; McConnell, Ky.; Murkowski, Alaska; Lott, Miss.; Lugar, Ind.; Martinez, Fla.; Roberts, Kan.; Sessions, Ala.; Shelby, Ala.; Snowe, Me.; Specter, Pa.; Stevens, Alaska; Sununu, N.H.; Thomas, Wyo.; Thune, S.D.; Vitter, La.; Voinovich, Ohio; Warner, Va.
Lieberman Party: Lieberman, Conn.
Not voting ---McCain, Johnson.