ABC makes the case. The argument’s simple: Romney has a prohibitive lead in delegates and it’s by no means assured that Santorum would pick up all of Gingrich’s voters if Newt dropped out. (According to yesterday’s Fox News poll, Romney leads Santorum head to head 49/44.) Which means, in a two-man race where Mitt wins some states and Rick wins some others, Romney actually has a better chance of ending up with a clear majority of delegates than he would if Newt hung in there and hoarded votes from Mitt. Keep Gingrich around, the thinking goes, and you might be able to hold Romney below 1,144, which means anything can happen at the convention. More from Chris Stirewalt:

[W]ith Romney so far ahead on delegates, Santorum would need to win 66 percent of the remaining delegates to win, a tough task for someone who has won only 27 percent so far. Even if he had won all of the delegates Gingrich had won so far, Santorum would only have 41 percent of the total, still 12 percent behind Romney…

[W]hen asked how they would vote without Gingrich in the race, the former speaker’s supporters don’t all shift to Santorum. Out of Gingrich’s 13 percent, Santorum gets 7 percent, but Romney gets 5 percent. Paul gets a point too.

While Santorum would move up, Romney would be pushed even closer to the finish line. Remember, for Santorum to win, Romney would need to collapse and start winning fewer delegates, not more.

In other words, if you’re dead set against Romney — as Newt clearly is — you’re better off playing a prevent defense to keep him out of the end zone than blitzing. Keep that five percent of Newt’s voters away from him even if it means denying Santorum seven percent and then hope that Team Sweater Vest can start beating Romney even in a three-way race so that there’s some sort of argument against Mitt at a brokered convention.

So there’s the mathematical reasoning for Newt staying in. Makes sense. Or does it?

“If he were out of this race, we wouldn’t just be beating Mitt Romney, we’d be crushing him,” Hogan Gidley, a senior adviser to the Santorum campaign, said Wednesday. “We wouldn’t have won every state that Romney won, but we sure would have won a lot more of them.”…

Under the rules in many states, if the winning candidate in a given Congressional district secures only a plurality of its votes, then he must share the district’s delegates with the second-place finisher. Only by winning more than 50 percent of the vote can a candidate win the entire delegate slate. By Mr. Gingrich’s logic, Mr. Romney would be in a better position to take more delegates in the absence of Mr. Gingrich because he would have more room to secure a majority in a head-to-head race against Mr. Santorum.

But the Republican nominating process is approaching a new phase in which more states will award delegates through a winner-take-all method by Congressional district. After April 1, the only two states that will award delegates proportionally within Congressional districts are North Carolina and Kentucky.

Here’s the bottom line strategically: Is there a scenario in which Romney makes it to the convention with a plurality of the delegates (as will almost certainly happen) but doesn’t end up with the nomination? Newt’s strategy here is to try to hold him to 1,000 delegates or something like that and then let backroom cloak and dagger eliminate Mitt, but I don’t see that happening in a three-way race. Even if Santorum closes the gap somewhat by winning winner-take-all states, Romney will still have more delegates, more votes overall (in all likelihood), probably more regional diversity to his state victories, and would certainly boast the most organized and well funded campaign of the final four candidates. He’d still have the best argument for the nomination. And even if Santorum finishes strong by winning a majority of the remaining primaries, Romney ironically could point to Gingrich’s presence in the race as evidence that we simply don’t know how things would have worked out in a two-man battle. Maybe Mitt would have beaten Santorum. Hard to say. In which case, shouldn’t we just choose the guy who ended up with the most delegates?

On the other hand, if Newt quits and we do get a two-man race, then Santorum at least has a shot at building an argument for the nomination. If he beats Romney head to a head in a majority of the remaining states, not only will he narrow the delegate gap but he can credibly claim that he was the preferred choice of Republican voters once they were asked to decide between him and Romney. And what if the polls are right and Gingrich’s voters end up splitting between Santorum and Romney such that Mitt wins the nomination with a majority of delegates before the convention? Well, that’s okay too. It would give Romney some extra credibility with the base headed into the general election. He could say, honestly, that he took on a consolidated conservative base and won, which makes him a legitimate victor. Better to give Santorum a clean shot and have him lose in a way that strengthens Romney than end up with a weakened, asterisked nominee after a brokered convention. The one hitch in all this is that I do think it’s slightly more likely that we’d see a dark-horse compromise candidate like Daniels or Christie nominated if Newt stays in and forces a three-way outcome than if he drops out and Romney and Santorum go head to head. In the latter case, if neither man ends up with a majority of delegates, there’ll be pressure on them to form a ticket. In the former case, with Gingrich muddying the waters by creating a third option, you could kinda sorta maybe possibly argue that the party is hopelessly split three ways and therefore we need to bring in an outsider. The odds of that are extremely long, but a bit shorter if Newt hangs in than if he drops out.

Via the Daily Caller, here’s Gingrich grumbling about Charles Krauthammer and the establishment. Exit question via Newt himself: Are his rivals and the media simply too small-minded to appreciate his ideas?