I can’t embed the clip but you can watch it here starting at around 42:00. The Daily Caller has the key quotes.

A challenge: Sketch out the process for me by which Democrats, with precious red-state seats in the balance, decide it’d be a good idea to try to choke down another vote on guns even closer to the midterm elections.

“I think we will bring the bill back before the end of the year… lots of Senators who thought it was safe to vote against it [April 17] because of the intensity [of gun-rights supporters] are not so sure any more,” Schumer told reporters at an April breakfast hosted by the Christian Science Monitor. “I do agree with Chuck that I think the issue will come back,” said Sen. John McCain, who supported an amendment to expand background checks during an April 17 vote… “I think we’re at a turning point… I think the numbers are getting a little more intense,” [Schumer] claimed. In a recent tour of conservative areas of New York state, “I heard from people who said ‘Keep at it,’ and I never heard from those folks before.”

Fast-forward to December. Mark Pryor’s trailing his Republican opponent by five points in early polling. Liberals are disappointed in him for his vote on Toomey/Manchin in April, but they’ve swallowed hard and decided to go out and vote for him purely in the interest of preserving a Democratic majority in the Senate. Suddenly Harry Reid declares that he’s got a new bill on background checks in the works, this one slightly watered down from the Toomey bill, and he’s going to force a new Senate vote on that. How excited are you to take that vote if you’re Mark Pryor or Mary Landrieu or Mark Begich? If you vote yes, your opponent jumps up and down and says that the left’s gun-control constituency has finally coopted you. If you vote no, liberals are angry because they’ve now been shafted twice on gun votes and might finally decide that your sorry behind isn’t worth trying to save after all. Even Scarborough, for all his nails-on-the-chalkboard sanctimony today, used to say things like this when he had to face voters rather than an MSNBC audience:

Scarborough told the NRA that his personal definition of an “assault weapon” was “anything the government would deny the people from protecting themselves against the government” and “anything the government would fear the people could use to protect their rights.”

Pols don’t “evolve” on this subject overnight the way they do on gay marriage. Realistically, there are two ways the calculus could shift to make pro-gun Dems change their minds. One is if Bloomberg’s group and other anti-gun orgs went all in to punish them, but there’s a major risk in doing that. National Journal explains:

Even running ads thanking the red state Democrats who voted for background checks, such as Louisiana’s Sen. Mary Landrieu, could hurt their reelection chances more than help in conservative states. Landrieu emphasized her vote was actually one to strengthen Second Amendment rights. Some analysts think that going after Pryor from the left on gun control could actually work to his political advantage in a general election. “Pryor could be so lucky to have people attacking him on [gun control],” Arkansas Democratic strategist and Talk Business columnist Michael Cook said before news of the Bloomberg group broke. “In some ways, that’s the best news for him, so he can say, ‘Look, I’m getting heat for standing up for your right to own guns.’”

Backfire. The other way, as gruesome and horrifying as the thought is, is for another terrible shooting to happen and serve as a rallying point for anti-gun forces. They seized the opportunity presented by Newtown to push all sorts of legislation that wouldn’t have done a thing to stop Adam Lanza, they’ll seize the next one too. They’re already thinking about it. But whether the next mass shooting would get the sort of singular media coverage that Newtown got or whether it would be swallowed up by other news is completely unknown. Gun-control fans need the public focused, and focus may be hard to come by later. How many sweet-ass game-changing propaganda posters can the dude responsible for the Obama “Hope” image be expected to churn out, realistically?

Actually, there’s one other way for this to come back on the radar with a chance of change. If something went very well for Obama over the next 18 months to alter the midterm calculus generally, putting Republicans on defense rather than offense, then you might see a few fencesitters look to curry favor with Democratic-trending voters by caving on background checks. For example, if the economy took off and O’s approval rating soared, with the 2014 electorate suddenly predicted to be bluer than you’d expect under a second-term liberal president, Pryor might reconsider and throw lefties a bone by voting yes on a very watered-down background checks bill. Given the way things are trending with ObamaCare, though, how likely do you suppose it is that summer 2014 will be a good time for O?