After last night’s twin triumphs in the Deep South for Rick Santorum, the future of the Republican presidential race has come down to one question: is there anything the Pennsylvanian can do to entice Newt Gingrich to drop out and endorse him or to just suspend his campaign? Though the delegate math still favors Mitt Romney, next week’s Illinois primary looms as yet another do-or-die test in much the same way Michigan and Ohio did. Santorum fell short in both of those states, allowing Mr. Inevitable to survive, though just barely. With polls showing Santorum only trailing Romney in Illinois by a few percentage points, the question is what can he do to make up the gap this time?

The obvious answer for Santorum is to somehow persuade Gingrich to get out of the race. I wrote last week detailing seven reasons why I thought the former speaker wouldn’t do it. I still think I’m right about that, but after defeats in Mississippi and Alabama, there is no longer any conceivable scenario by which Gingrich could be nominated. His mere presence on the ballot helps divide the conservative vote and might, as it did in Michigan and Ohio, allow Romney to squeak out a victory. If Gingrich is at all inclined to bargain with Santorum then his bargaining power will never be greater than it is at this moment. That leaves us to ponder whether the speaker might be willing to accept a promise of a place on the ticket or a cabinet post in exchange for backing Santorum.

On Santorum’s side of that equation, there are two good arguments against making such an offer.

One is that it is possible Gingrich is about to fade out of the picture anyway. Why pay a high price for his support when it might not be worth much in the coming months?

The other is a bit more principled. Having seen what Gingrich was like when he was Speaker of the House, could Santorum really bring himself to put such an inconsistent and often unfocused person only a heartbeat away from the presidency?

Gingrich may also reason that his bargaining power will increase rather than decline if neither Romney nor Santorum wins a majority of delegates by the time the primaries end. Though he may not be so foolish as to believehe could be a compromise solution in a brokered convention, it’s hard to imagine Gingrich being willing to toss in the towel at this moment when he still thinks he might be able to play the kingmaker this summer.

Yet, if Gingrich really wants to remain a factor in the presidential race, a deal that made him Santorum’s running mate might be his best bet. Indeed, one can actually imagine him getting the equally loquacious and egotistic Vice President Joe Biden to agree to Lincoln-Douglas style debates.

As for Santorum, as unpalatable as the prospect of getting into bed with a prima donna like Gingrich may be, he also needs to ask himself how much he really wants to be president and whether he is willing to pay any political price to win.

If Gingrich stays on the ballot rather than on the sidelines, the odds are Romney finds a way to win Illinois and still manages to take the nomination. For all of his bravado about the delegate math not mattering, Santorum understands at this stage, it is everything. Unless he can get his one-on-one matchup with Romney and get it soon, Santorum will probably fall short of the mark. A grand deal with Gingrich that promised him the vice presidency might actually be the only way he can achieve this scenario.

Of course, all this is pure speculation. It will probably never happen due to Santorum’s reluctance to deal with Gingrich and the former speaker’s delusions about his own non-existent chances. But if Santorum and Gingrich really believe Romney must be stopped, then sooner or later they are bound to think about the possibility of a deal.