Greg Sargent at WaPo:

With red state Democratic Senators remaining skittish about embracing Obama’s gun proposals, at least two top Democratic donors are stepping forward and vowing to withhold any and all future financial contributions from any Democrats who don’t support the centerpiece of Obama’s plan: Expanded background checks.

Kenneth Lerer, a New York businessman who is chairman of Buzzfeed.com, and David Bohnett, a technology entrepreneur and philanthopist based in Los Angeles, are both major financial supporters of Democratic candidates, having each given scores of large contributions over the years. ... Neither will give another dime to any Senate Democrat who does not support expanded background checks, I’m told — and both will suggest to other donors that they do the same.

Right fucking on. I'd just suggest that do the same thing for assault weapons.