After a decisive loss in Illinois last night, will Rick Santorum heed his latent pragmatic side and bow to the inevitable, or will he go guerilla, take to the hills and continue to cut and bleed Mitt Romney?

So much of this campaign must be personal for Santorum. By now, he probably can’t stand Romney and his team and is incredulous that such a phony conservative as the former Massachusetts governor is winning so ugly and so weakly. He must imagine that if he had but half Romney's campaign war chest, the results would be very different. And, of course, Santorum could be buoyed by the technical possibility of victory and by the support of his core and rabid supporters.

Against all this, he may hear another voice — that of his party establishment, with whom he has always had an ambivalent relationship. Its squeeze on him to gracefully exit and unite the party got much tighter last night.