In case anyone had any doubts about Newt Gingrich's true motivations, they have now become glaringly apparent as he continues his pointless (I won't say, "Quixotic," because that would imply that there's a higher principle involved) quest for the Republican presidential nomination.
Newt's driving force has always been self-aggrandizement and satisfaction. That isn't to say that he doesn't try to cloak his base urges in the silken garment of patriotism and higher purpose when it suits him (it was his "passion for his country," he claimed, that caused him to cheat on his first wife), but the fact is that he is no longer in this race to win it.
Sheldon Adelson, his Las Vegas bankroller, must have his own agenda for acting as the former speaker's almost unique source of campaign funding. It can't be to stop Romney, for Gingrich's continued presence in the race splits the conservative opposition vote with Rick Santorum.
By staying in, Newt is only hurting his party—the party he purportedly loves—by ensuring that a heavily damaged candidate limps to the finish line.
Of course, the consequences of Newt's vanity have never slowed him down in the past. Remember when he shut down the government in the 1990s over his pique at being seated in the rear of President Clinton's aircraft?