Senator Olympia Snowe (R-Maine) issued a statement Monday saying she would oppose the motion to proceed to consideration of the defense authorization bill, the legislation that includes language seeking repeal of Don’t Ask, Don’t Tell.

While Snowe said she believes Don’t Ask, Don’t Tell (DADT) warrants a “thorough review,” she said she believes the Senate should hold off its vote on repeal until after the Pentagon submits its report on implementation of repeal. Snowe said she also objects to Senate Majority Leader Harry Reid’s limiting of debate to just three amendments—DADT, an immigration measure, and a measure to change Senate rules concerning secret holds on nominations.

Reid said late last week he would allow the Senate to take up only those three amendments to the defense bill prior to the mid-term elections. Only after mid-terms, said Reid, would the Senate resume and finish debate on the funding measure.

Snowe was one of seven senators that pro-repeal advocates had hoped to win over to vote for proceeding on the bill. Vice President Joe Biden has said Democrats have 55 votes to repeal DADT, but not necessarily the 60 to break the Republican filibuster. Senator Susan Collins (R-Maine) is also reportedly uncomfortable with a limit on amendments; and Senator Jim Webb (D-Va.) wants to consider a fourth amendment—one aimed at stopping a cut in military command posts in Virginia.

Republicans have also been complaining that two of the three amendments are non-defense related and shouldn’t be part of the discussion. But Senator Carl Levin (D-Mich.), chairman of the Senate Armed Services Committee, disputed that argument. On the floor of the Senate Monday, he itemized all the non-defense related amendments that have been considered on the defense authorization bill in previous years—including years in which Republicans were in the majority. In particular, he emphasized an amendment on campaign reform offered in 2000 by Senator John McCain (R-Ariz.).

Much of the news leading up to tomorrow’s vote has been focused on the involvement of popular performer Lady Gaga, who has used her various media platforms to direct attention to the effort to repeal DADT. On Monday, she led a rally in Maine, hoping to persuade the state’s two senators—Snowe and Susan Collins—to vote for cloture on Tuesday.

The filibuster vote is due to be on the floor at approximately 2:15 p.m. Eastern, Tuesday.