The Public Policy Polling outfit has been offering Mitt Romney a bottomless cup o’ misery this last week. It was the first to show Rick Santorum passing Mitt like a stalled Beamer nationally, and the first to show him ahead in Michigan, too. Now comes a PPP general election survey indicating the mightiest pillar of Romney’s candidacy, his “electability,” is looking shaky.

Tom Jensen spells it out:

PPP’s newest national poll finds Romney trailing Obama by 7 points at 49-42, while Santorum trails by only 5 points at 49-44.

This is a new development in the flavor of the month game. Over the previous 6 months when Romney first trailed Michele Bachmann, then Rick Perry, then Herman Cain, then Newt Gingrich in our national polling he still did on average 6 points better than them in our general election tests.

Now these findings don’t necessarily mean Santorum is really more electable than Romney. Like Santorum’s overall lead, his relatively strong showing in test heats against Obama is significantly attributable to the easy ride he’s had in the GOP contest so far; about the only negative attacks he’s attracted from rivals, in debates or in ads, have been designed to undermine his standing with hard-core conservatives, not with the general electorate.

Santorum’s relentless extremism on cultural issues–up to and including his enthusiastic embrace of a national “Personhood Amendment” similar to the initiative recently trounced by the voters of that secular-socialist stronghold Mississippi–is not going to go over well in a general election. Nothing about his economic platform makes him more attractive to general election voters than Mitt Romney, or for that matter, the House GOP. Then there’s the inconvenient fact that the last time Rick faced a general election, as an incumbent U.S. Senator, he lost by 19% (yes, it was a bad year for Republicans, but not that bad).

So at some point, Santorum is likely not going to look all that electable The problem for Romney is that this “some point” is not right now. And to the extent that the entire GOP nominating contest has represented a frantic search by conservatives for an alternative to Romney who isn’t a sure general election loser, the activists of the GOP “base” probably won’t look too deeply at any available evidence they’ve finally found one in Santorum.

Unless this survey is an outlier, it might help convince Romney to ignore the counsel of those who have argued he can’t afford to “go negative” on Santorum as he did on Perry and Gingrich. Could be he can’t afford to do anything else.

Ed Kilgore

Ed Kilgore is a political columnist for New York and managing editor at the Democratic Strategist website. He was a contributing writer at the Washington Monthly from January 2012 until November 2015, and was the principal contributor to the Political Animal blog.