Poll analysis: Anything can happen tonight

And all of that brings us to Thursday, which The Huffington Post’s Jon Ward described as “the most eventful day of the Republican primary season.” It featured Rick Perry withdrawing from the race and endorsing Gingrich, Gingrich’s former wife Marianne Gingrich taking to the airwaves to accuse the former speaker of seeking an “open marriage” to allow him to keep a mistress, and a nationally televised debate featuring some of the most raucous sparring yet among the candidates.

So while the recent surge in support for Gingrich is undeniable, the events of the last 24 hours have the potential to produce new and unexpected changes in voter preferences. There is some precedent for such shifts, including the events just prior to New Hampshire’s 2008 Democratic presidential primary and a special congressional election in 2009 in New York’s 23rd Congressional District.

The last 72 hours before the New York congressional election featured the withdrawal from the race of the Republican candidate, Dede Scozzafava, followed by her endorsement of the Democrat, Bill Owens. Three polls conducted on the eve of voting all showed Tea Party candidate Doug Hoffman surging ahead, with leads ranging from 5 to 17 percentage points. Yet, when the votes were counted, Democrat Owen had defeated Hoffman by a narrow margin.