But if Newt Gingrich were to stay in the race, he’d be following a different sort of precedent: candidates with no real shot at the nomination who have hung around anyway, because they represented distinct party constituencies (like Jesse Jackson in 1988) or because they hoped to benefit from a consolidation of “buyer’s remorse” voters after it was all decided (such as Jerry Brown in 1992, and, for a while, George H.W. Bush in 1980) to boost their status as Big Dogs. As was amply demonstrated by the attacks on Gingrich from conservative opinion-leaders after his win in South Carolina, he is not the universally acknowledged leader of an important ideological faction like Reagan in 1976 or Ted Kennedy in 1980. He also has none of the vast financial resources of a Reagan or a Kennedy, and given his consistently poor general election poll standings (especially as compared to Romney) he cannot make the kind of electability argument that supported Bush in 1980 or Hart in 1984.

And when you look at the actual timetable of this year’s nominating contest, it doesn’t give Newt a lot of natural advantages. In the February contests, he faces Romney in his home state of Michigan and Mormon-heavy Nevada, along with resource-intensive caucuses in Colorado and Minnesota—contests where Ron Paul is sure to split the anti-Romney protest vote. He’s not even on the ballot in Missouri. His best shot is the Arizona primary, and that’s an uphill battle. It’s also not clear when (or if) Rick Santorum, who will take most of his votes from the pool otherwise available to Newt, will drop out.

His odds on March 6, Super Tuesday, are no better. Gingrich must win Georgia (particularly after his endorsement by fellow-Georgian Herman Cain), is not on the ballot in Virginia, can’t win in Massachusetts, and again has to deal with an assortment of expensive caucuses scattered around the country. If he survives all that, he must then navigate another series of probably-hostile caucuses before arriving at the cash-sucking oasis of Texas on April 3. Then comes April 24, when a battery of northeastern primaries (including delegate-rich New York and Pennsylvania) looks impossible. Remember, too, that the ban on winner-take-all primaries ends on April 1, which will help the front-runner bank big delegate totals.