Even though he doesn’t have the votes, Senate Majority Leader Harry Reid (D-Nev.) will move ahead on legislation Wednesday to expand background checks for gun sales. …

“We don’t know if we have 60 votes, but we don’t know that we don’t have 60,” a Democratic aide said. “It will be very close.”

Reid, however, has counted enough undecided senators to give him a shot, albeit one with long odds, at just clearing the 60-vote threshold. …

With Begich and Pryor considered likely to vote against it, Democratic leaders need to find seven Republican votes. That could be mission impossible.

So far, only four Republicans have committed to the proposal or are leaning toward voting yes: Toomey and Sens. Mark Kirk (Ill.), Susan Collins (Maine) and John McCain (Ariz.), who is not a certain yes.