Sen. Jeff Flake (R-Ariz.) may have breathed new life into a defeated amendment to expand background checks for gun buyers. The conservative is reportedly open to reversing his opposition, provided an exemption is added for online sales between friends.

The reported about-face is possibly the first indication that the Senate could resurrect the bipartisan legislation, which was hammered out by Sens. Joe Manchin (D-W.V.) and Pat Toomey (R-Pa.). In a demoralizing defeat for gun-control supporters, the amendment last month fell six votes shy of the 60 needed to get past a GOP-led filibuster.

Flake is one of several lawmakers who have faced an angry backlash for opposing the tightened checks, which are backed by an overwhelming majority of the public. Indeed, Flake himself has said his plummeting poll numbers in Arizona put him somewhere "below pond scum." 

If Flake changes sides, it could give a boost to gun-control supporters who remain committed to passing the bill. Taking Senate Majority Leader Harry Reid (D-Nev.) into account (he voted "no" only for procedural reasons), Manchin and his allies "need to convince five senators to go from 'no' to 'yes,'" says Dana Bash at CNN.

Flake is a good place to start if they hope to change the math. He is close to former congresswoman Gabby Giffords, a fellow Arizonan who, along with her husband, has been putting serious pressure on Flake to support the measure. 

Even if Flake is having second thoughts, the bill would need four more votes. Reid says he can deliver another Democrat or two, while other Republicans are reportedly under pressure to flip their votes.

Sen. Kelly Ayotte (R-N.H.) is seen as one of the more likely to change positions. Like Flake, she has taken a beating in her home state for opposing the bill, replete with a public scolding from the daughter of a victim of the Newtown school massacre. In a recent op-ed, Ayotte wrote, "I support effective background checks," though she said "we shouldn't be expanding a flawed system."

"Whether that means she's resolved to stick to her guns by opposing T-M or whether she’s merely floating a trial balloon here to see if it’s enough to get gun-control fans to back off, we'll see," says Allahpundit at Hot Air.

However, even if supporters of Toomey-Manchin are not where they need to be yet, "the bullish talk from Democrats — from leadership on down — is yet another indication that the party feels good about the fallout from the failed gun vote and is increasingly eager to try again," says Sam Stein at The Huffington Post.

And if a minor tweak gives Flake a reason to change his vote, Toomey-Manchin could be back in business, because Flake will provide cover for anyone else looking to switch.