A number of analysts have suggested that Rick Santorum’s surge demonstrates Mitt Romney’s profound inability to galvanize working class white voters — which, if true, goes directly to the heart of Romney’s case for electability.

Some new Gallup numbers strongly buttress this case — in the past two weeks, Romney has suffered sizable losses among non-college Republicans and GOP-leaning independents, while Santorum has posted huge gains among them.

The Gallup toplines released this morning show Santorum now beating Romney by 10 points, 36-26, among Republican voters and GOP-leaning independents. That’s a huge shift from two weeks ago, when Romney led by 37-16.

Gallup has just posted a further breakdown of the numbers. It includes changes among college versus non-college voters (since the percentage of minority Republicans is so low, it seems fair to look at these as a rough guide to downscale whites); and changes among self-identfied conservatives. The highlights:

* In the last two weeks, Romney has dropped nine points among non-college Republicans and GOP-leaning independents, from 32 percent down to 23 percent. Santorum, meanwhile, has jumped 22 points among them, from 15 percent up to 37 percent.

Ginrich has dropped 12 points among these voters — and it seems all of those losses have gone to Santorum.

Meanwhile, Romney has remained relatively stable among college grads, and Santorum has jumped only 14 points among them — eight points lower than his gains among non-college voters.

* Among self described conservative Republicans and GOP-leaners, Romney has dropped nine points, from 33 percent down to 24. Meanwhile, Santorum has jumped 22 points, from 20 percent to 42 percent.

The other day, Ron Brownstein asked whether Santorum is “demonstrating that his mix of economic nationalism and cultural conservatism can galvanize the GOP’s burgeoning working-class wing.” These numbers seem to answer that question with a resounding affirmative.

And if this trend continues, it will continue to underscore Romney’s White Working Class Problem and the difficulties it could pose in a general election.