Rick Santorum has a problem: If he doesn’t already, he soon will lack a justification for continuing his campaign.

It is dawning on conservatives that the idea of a brokered convention is ludicrous and fundamentally anti-democratic. Rich Lowry writes that “even if he’s short of 1,144, Romney will almost certainly have the most votes and the most delegates and therefore . . . a moral claim on the nomination. To nominate someone else instead at that point — someone who received fewer votes, or perhaps didn’t run at all — would be an extraordinary thing.”

Because it is unpalatable, Santorum has now taken to claiming he can get to 1,144 delegates. But that would require that he get more than 67 percent of the remaining delegates. If he loses in Illinois tonight, that number will go up. So what does he do?

He makes up a cock-and-bull story about how he really has more delegates than the 253 that The Post, the Associated Press, every network and the GOP reflect. If he did, that would depend on two assumptions that are, candidly, ludicrous.

The Fix explains:

One is that the 79 delegates Arizona and Florida are currently awarding on a winner-take-all basis to Romney will eventually be awarded proportionally, since no state holding a primary before April is supposed to use the winner-take-all method.

And the second is that Santorum is getting more delegates in caucus states than the results suggest. This is because, while the delegate projections in those states are based on the results of a straw poll, the actual selection of the delegates is a separate process in which a campaign with a good organization can win more delegates than initial projections.

In both cases, Santorum’s campaign is engaging in wishful thinking.

Understand that Santorum’s “theory” requires a rule change after the fact at a convention in which he will not have a majority of delegates. Brian Bolduc spoke with some delegates who dismissed this out of hand:

Lenny Curry, chairman of the Florida Republican party, says this contention is “nonsense.”

“I think the challenge is absurd,” he tells NRO [National Review Online]. “Every candidate came to Florida and campaigned here with the understanding that we were winner-take-all. Heading up to the primary date, no one questioned it. Florida is winner-take-all; we expect it to be winner-take-all at the convention.”

Meanwhile, Jim Bopp, a member of the RNC rules committee, says such a contest would have no merit. “Proportionately is only required for those states that go between March 6 and the end of March. People that went before March 1 can do winner-take-all.”

As for his theory that there are really more delegates lurking somewhere, Santorum lacks an factual indication that this is true. Again, the Fix: “Santorum’s campaign has failed to qualify for full slates of delegates in several states — an organizational failure that has cost him dearly. But we are to believe that this same campaign organization has been so good in caucus states that it will out-perform its showings in the caucus straw polls?”

Santorum is grasping at straws, trying to keep the illusion of viability afloat. But viability depends on a presidential primary process other than the one he is in. Santorum won’t level with voters or the media (which have taken to mocking his phony math). If he did, he’d have to explain what he is still doing in the race.

But here is the thing: We will soon reach the point at which there are not enough outstanding delegates for Santorum to get to 1,144. Every Republican Party official and news outlet will recognize that. And what’s he going to do or say then?