Here is what the Granite State looks like right now, according to the RCP Average. Romney is at +10.8 percent, still hanging on to a much-eroded lead (his total poll share is 33.8 percent). Gingrich is in second (23 percent), Paul third (16 percent) and Jon Huntsman fourth (10.5 percent).

All of that would matter very little the minute Paul wins Iowa. If he can beat Gingrich there, the real contest in New Hampshire will be between Paul’s defiant leave-us-alone-and-bring-the-troops-home Republicanism and Romney’s managerial competence. Paul seems a better fit for New Hampshire voters, and Iowa can remove the taint of unelectability (see Obama, Barack).

Here comes the fun part. Suppose the implausible occurs and Paul wins Iowa and New Hampshire, with Gingrich and then Romney coming in second in the two contests. South Carolina two weeks later is the Republican Party’s firewall to exclude troublesome candidates. They used it to stop John McCain in 2000 and Mike Huckabee in 2008.

To stop a candidate, you need a candidate, preferably along with a few spoilers who can carve into the insurgent’s vote share. If Gingrich and Romney both place second, neither would be the obvious default candidate. Would Romney drop out like he unexpectedly did at CPAC last time? Would Gingrich stand down because he can’t stand Paul’s national not-so-greatness politics?