There are several reasons, not the least of which is the man's colossal ego. It seems to render him unable to recognize that the party he professes to love could possibly do better without him as a candidate at the supreme celebration of American politics, the national party convention.
Mr. Gingrich may be part historian, but he also is in large part a showman. And there is no stage in the political drama equal to the party convention. You don't have to be the winner to show up at the convention and strut your stuff. Although bad feelings toward a stubborn Mr. Gingrich could deny him a speaking role in Tampa this summer, the party can ill afford another open internal fight then.
There is, however, more than Gingrich ego behind his repeatedly announced decision to stay in the Republican race all the way to the convention. While nominal frontrunner Mitt Romney has made "the math" the strongest argument for his claimed inevitability, Newt can add, too. He knows that as long as three candidates capable of picking up delegates -- Rick Santorum, Ron Paul and himself -- remain in contention, there's a chance that Mr. Romney will fall short of the majority required for nomination.
In a two-way race, getting the nomination is an easy accomplishment for the frontrunner -- all it requires is getting more delegates than the other guy. But in a four-man race, the practical math says that to win a majority, a nominee has to corral more delegates than the other three contenders combined. A frontrunner who seems able to depend only on roughly an average of 35 percent of the primary and caucus votes in his own party is hardly a guaranteed victor in the fall.
So it's incumbent on Mr. Gingrich, if he hopes to block Mr. Romney's nomination (or Mr. Santorum's for that matter), to remain in the contest along with Mr. Paul, who come what may will march to his own drummer into Tampa. For Mr. Gingrich to bow out now would set up the two-man fight for the "true conservative" mantle between Mr. Romney and Mr. Santorum, leaving Newt out in the cold.
In a sense, Mr. Gingrich now faces a Catch-22. If he stays in, he sets himself up for further humiliation as a loser who can't face reality and who is willing to damage his party by remaining a roadblock to a pre-convention decision on its nominee. If he gets out, he facilitates such a decision, obviously benefiting both his major rivals and in any event anointing Mr. Santorum as the next champion of the GOP right wing.
At age 68, Mr. Gingrich may regard the approaching convention as his last hurrah. It would be characteristic of him to try to turn a sow's ear into a silk purse with another grandiose presentation of his greatness before the biggest national audience still available to him.
As for Mr. Santorum, who is only 53, the same convention can be a no-lose situation. He can either pull off an unlikely upset over the constitutionally hapless Mr. Romney or establish himself as the great white hope in the GOP for the next time around.
This primary/caucus season is increasingly becoming a battle for the soul of the Republican Party, with its old establishment under assault by a combination of tea party and evangelical Christian extremists. Either way it turns out, Mr. Santorum can emerge a winner despite his narrow ideological platform, poised to lead the GOP further away from the moderate mainstream of American politics down the road.
Mr. Gingrich, of course, could surprise everyone, including himself, by making as his final act a personal sacrifice. He could bow out before the convention and give the "true conservative" base a clear shot at stopping Mr. Romney short of the nomination. He could, as Mr. Santorum said in another reference, take one for the team. But that wouldn't be Newt, would it?