News that Herman Cain may be “reassessing” his presidential campaign deserves the attention it has garnered. With Mitt Romney seemingly unable to increase his percentage in the polls, the fewer “anti-Romneys” in the race, the greater the odds are that one of them might just be able to corral enough votes to win.

The trouble is that there is seldom an incentive for political candidates — especially the major candidates who’ve already made it this far — to get out a race prior to New Hampshire.

This, of course, has consequences. It keeps voters who might otherwise coalesce around another candidate in a sort of primary purgatory.

That’s arguably what happened in 2008, when conservatives waited until it was too late to begin rallying around Mitt Romney. Cain’s possible exodus, as such, could change things in an otherwise unpredictable way — possibly ensuring that what happened in the 2008 GOP primary isn’t repeated again in 2012.

Barring such an event, it indeed looks like we could be witnessing a repeat of ’08 — with Mitt Romney this time playing the role of John McCain. As was the case at this point in the ’08 cycle, the field is still relatively large, with only one serious candidate having exited. (This deserves an asterisk: Popular leaders like Mike Huckabee and Sarah Palin — never officially candidates — flirted with the idea of running this time, but never did. And in ’08, candidates like Jim Gilmore, Tommy Thompson, and Tom Tancredo did run, but flamed out early. This time around, Rep. Thad McCotter and former Gov. Tim Pawlenty — once considered a frontrunner — have officially bowed out.)

Pawlenty is essentially this year’s Sam Brownback — a candidate with high expectations who floundered early. In Brownback’s case, he got out in October of 2007, promptly endorsing John McCain. (Pawlenty — playing the 2012 version of Brownback’s role — endorsed Romney.)

After Brownback’s departure, the rest of the ’08 field — with the exception of Tancredo (who had no chance of winning) — battened down the hatches until the voting began. Rep. Duncan Hunter lasted until January 19, 2008. Former Sen. Fred Thompson dropped out on January 22. Former Mayor Rudy Giuliani held out until January 30. Former Gov. Mitt Romney withdrew on February 7 (at this point, it was clear John McCain would be the nominee). Former Gov. Mike Huckabee stuck it out all the way to March 4, 2008. And Rep. Ron Paul didn’t officially suspend his campaign until June 12.

We know how the story ended. John McCain won. But how much of it had to do with the size of the field, versus McCain’s performance? What if Mike Huckabee had become embroiled in scandal, and exited in, say, December of ’07 — instead of exiting in March of ’08?

It’s hard to predict what might have happened, but it’s at least possible to think Mitt Romney (who finished second there) might have won Iowa — and then, ultimately, the nomination. If scandal pushes Herman Cain out of the race, it could have a very real impact…