Advocates are also eying Republican lame duck Sens. George LeMieux of Florida, Charlie Crist’s former chief of staff, and Judd Gregg of New Hampshire, though Gregg voted no on cloture in 2007.

Snowe, Hutchison and Hatch all face a reelection contest in 2012 and therefore potential primary challenges. They’ll “likely be on their best behavior this time around,” said a former GOP senate aide…

Using an algorithm that takes into account past votes, public statements, looming reelection bids and human intelligence, the WhipCast by the Davis Intelligence Group found a 33% chance that cloture would pass.

“Our proprietary vote simulation and prediction engine suggests that Sen. Reid has a tough hill to climb in his battle to overcome a filibuster to the DREAM Act,” said Sean Davis, managing partner of the company, a political research firm for investment professionals. Davis noted that Democrats would “likely be hesitant to vote for anything that resembles amnesty for illegal immigrants.”