Conventional wisdom is that the Republican presidential field is set, and that it is much too late for a new candidate to enter the race.
In years past, that would be absolutely correct. Over the last few decades, dozens of primaries and caucuses have been shoe-horned into the opening weeks of the election year, with the tendency on the Republican side for the front-running candidate to score a quick knockout.
But next year, the arrangement of the primary calendar is much different. It is less condensed at the front, much more loaded with events at the back, with the prospect of a viable, late-starting candidate quite real.
This is not to say that it will happen, but simply to note that it could. Such a scenario could not have unfolded in 2008, when the early January events were followed in short order by an early February Super Tuesday vote-fest that involved nearly half the country.
But the elongated layout of the nominating calendar this time provides the opportunity for a late-starting candidate to emerge. Should Mitt Romney stumble badly in the January events in Iowa, New Hampshire, South Carolina and Florida, another establishment Republican could enter the race in early February and still compete directly in states with at least 1,200 of the 2,282 or so GOP delegates. Many of them will be up for grabs after April 1 when statewide winner-take-all is possible.
Similarly, should non-Romney alternatives led by Newt Gingrich, Michele Bachmann and Rick Perry fall flat in the January contests, there would be time for the conservative wing of the party to find a new champion to carry its banner through the bulk of the primary season.