On Monday I reported on an exchange I had with RealClearPolitics’ Jay Cost on my contention that the political landscape is likely to get a lot rockier for Republicans in 2012, no matter how well they do this November.

I don’t want to keep this exchange going perpetually, but Jay’s last update raises two issues that I want to mention before turning the page. First, he quite rightly argues that the governing record of the Obama administration, and the policy and message response of the GOP, could have at least as large an impact on 2012 as the demographic factors I stressed in my original piece. No question that is true, and that’s the sort of thing I write about nearly every day. But I don’t get the sense that Republicans are paying much attention to the changes in landscape that are going to occur semi-automatically as we move from a midterm to a presidential cycle — changes that will complicate every step they take. And that was the main point of my Salon article, which was by no means some sort of definitive personal manifesto on everything related to the 2012 elections.

But Cost makes an argument on another question where I am much less inclined to agree with him: How likely it is that a “dark horse” will emerge in 2012 to revolutionize the Republican presidential field? Sure, again, anything’s possible, particularly this far from Election Day 2012. But as I observed in my original piece, presidential campaigns these days almost have to develop long in advance, particularly for “dark horses” who have to establish name ID, raise a lot of money, and then perform the ritual of semi-residence in early primary and caucus states. (I suspect there may be some understandable confusion on Jay’s part based on the assumption that I was arguing that various “dark horse” candidates would be poor general election candidates, but my main contention was that Republicans had a weak field of leading candidates, and that none of the dark horses had the chops to get the nomination).

Jay thinks my lukewarm assessment of lesser-known potential Republican presidential candidates like John Thune, Mitch Daniels, Mike Pence and Tim Pawlenty is just a matter of partisan bias. He even makes the (to me) astonishing statement that Thune’s appeal is no more superficial than Barack Obama’s in 2008 (which I’d say reflects more than a little partisan bias). So let’s think about what makes a “dark horse” candidate formidable, at a time when there are no kingmakers to pluck a Warren Harding out of obscurity and lift him to the nomination. I’d say the minimum qualifications are one if not more than one of the following qualities: exceptional public renown; special identification with a major cause or new ideology; a particular appeal to important and previously underrepresented constituencies; a remarkable public personality; or a novel approach to presidential candidacy. To some extent, dark horses these days, unless they just get lucky, need a candidacy that is in some respect historic. Giant fountains of money also help, though none of the people being “mentioned” as dark horses in 2012 are named Michael Bloomberg. Geography can matter, too, but that’s usually not dispositive unless a candidate’s geographical origins are somehow “historic” or unique.

So let’s look at Cost’s list of potentially formidable 2012 dark horses with those criteria in mind. John Thune is a minor legend in Republican insider circles because he narrowly won a GOTV-driven slugfest in the heavily Republican state of South Dakota in 2004, thus beating Senate Minority Leader Tom Daschle. This was a testament to Thune’s personal attractivenss, durability, and willingness to toe the party line, but these are not typically the qualities that vault someone from obscurity to a presidential nomination. So far as I can tell, he is not particularly known for any policy positions, issues, or personification of any underrepresented constituency group or geographical grouping. Yes, he is broadly acceptable to every major element of the GOP, but “acceptability” is a quality that matters only when one is no longer a dark horse, and in any event, who isn’t “acceptable” in these days of monochromatic conservative uniformity in the GOP? That is also the problem of Indiana Rep. Mike Pence, were he to run for president. He’s a guy beloved of movement conservative types for representing the movement conservative point-of-view in the House GOP Caucus. But are self-conscious “movement conservatives” really a voting faction in the GOP nominating process, and are they so aggrieved by the rest of the field that they will coalesece around Pence? There’s no particular reason to think so.

Mitch Daniels is another insider heart-throb, in no small part because he was a major Washington figure as OMB Director under Bush 43, and then successfully took his act mainstream by being elected and then re-elected governor of a usually Republican state where Republican statewide candidates have often struggled. I can see the argument that Daniels’ resume equips him to become the symbol of the suddenly preeminent conservative issue of fiscal discipline (though oppo researchers would have great sport with his responsibility for Bush budget deficits). But again: is that a quality that so separates him from the field that he can make it his own? And does he have other personal or representational characteristics that could give him the rock-star aura to come out of national obscurity, and, say, win the Iowa Caucuses? Maybe, but the evidence of that isn’t obvious.

And then there’s Tim Paw, and it is true that he coined a very interesting and serviceable slogan in talking about “Sam’s Club Republicans.” It is also true, as Jay notes, that Reihan Salam and Ross Douthat turned that slogan into a pretty unorthodox agenda for the GOP–so unorthodox, in fact, that it was generally rejected or ignored by conservatives, aside from its very orthodox endorsement of tax subsidies for marriage and child-bearing. But that has little or nothing to do with Pawlenty, who has been conventionally conservative in his proto-presidential campaign, and whose Big Idea seems to be the ancient and completely symbolic chesnut of a balanced budget constitutional amendment.

Is there anything about these putative “dark horses” that makes any of them particularly stand out, other than as “acceptable” alternatives to the front-runners if one of them happens to get a one-on-one contest? I don’t see it. And there’s certainly nothing about any of them that is comparable to the Democratic “dark horses” that Jay Cost cites in his own piece: John Kennedy, Jimmy Carter, Bill Clinton and Barack Obama. Kennedy was the first serious Catholic candidate for president since Al Smith; Carter was the first serious Deep South candidate since the Civil War; Clinton ran aggressively against the pieties of his own party; and Obama became a huge national celebrity as a state senator and went on to beat a legendary Democrat in virtually all-white Iowa.

Until someone emerges on the fringes of the Republican presidential field who can truly separate him- or herself from the field, anyone is entitled to some serious skepticism about the faith of many Republicans that they’ll wind up with a presidential candidate who doesn’t share the handicaps of the established field.

As for the weakness of that established field, check out Nate Silver’s 538.com post that comments on my exchange with Jay Cost and offers some objective evidence that the elephants running in 2012 don’t quite match the donkeys who ran in 2008.

This item is cross-posted at The Democratic Strategist.