I’ve been mostly ignoring the various “Romney 2016!” trial balloons floated by various parties over the last six months or so (including by some of my dear friends, alas), but now that someone as sober and well-informed as Byron York has weighed in with a “this could happen” column, it’s worth saying something about why the possibility keeps coming up.

Part of the answer can be found in Henry Olsen’s helpful analysis, from earlier this year, of how exactly Republican presidential primaries tend to shake out. Olsen offered a four-group typology of G.O.P. primary voters — secular conservatives, religious conservatives, moderate conservatives and Rockefeller-Republican centrists — and argued that the nomination almost always goes to the candidate who can rally the moderate conservatives and co-opt elements from the other constituencies while fending of challenges from the right and (sometimes, though less often) the center. There are different ways to do this (as evidenced by George W. Bush and John McCain’s very different paths to the nomination), but the trick doesn’t change that much from cycle to cycle — you want to seem conservative enough but not too right-wing, electable but not a liberal sellout, a safe choice for donors who also makes the party’s activists feel respected. You don’t win by running against those activists (as McCain did in 2000, and Jon Huntsman did in 2012), and you also don’t win by running as an ideological insurgent; you win by straddling dispositional and ideological conservatism, raising lots of money, and promising the best chance of victory in November.

Which is why, if there hadn’t been a New Jersey traffic scandal, we wouldn’t be talking about Mitt Romney right now — because Chris Christie would be sitting squarely in that moderate-conservative, donor-reassuring, I’m-electable-but-also-conservative-enough space, and the big question would be whether the potential ideological insurgents (Ted Cruz and Rand Paul, notably, though maybe others) could improve upon the showing of their predecessors and break the moderate-conservative lock. But because Christie was knocked down, weakened, tainted, and because we don’t know how he’ll bounce back (and I’m more skeptical of his bounce-back potential than some), that moderate-conservative space suddenly looks emptier than it usually does: Jeb Bush is flirting with trying to occupy it — and tellingly, in York’s story the Romney folks make it clear he wouldn’t run if Jeb did — but I still bet he doesn’t run, and then you’re left with Marco Rubio (whom Romney’s team presumably vetted, so maybe they know something we don’t), Paul Ryan (who doesn’t want to run, pretty clearly) and a passel of governors, the most prominent of whom, Scott Walker, could still lose his own re-elect. So you have more of a void, of sorts, compared to past campaigns … and if you squint just right, that void’s shape looks suspiciously like a certain square-jawed, flawlessly-coiffed, Mormon millionaire-philanthrophist-grandparent, doesn’t it?