Ross Douthat recently discussed the quarrel between Chris Christie and Rand Paul in the context of the vacuum left behind by the GOP’s missing realists:

So as odd as it is, especially for anyone who experienced the Bush era, to hear a non-interventionist Republican attacking a tough-on-terror Republican for being too “liberal,” given the current shape of Republican opinion Rand Paul’s framing of his debate with Christie is defensible: By invoking 9/11 to defend the N.S.A.’s surveillance programs, the New Jersey governor was arguably attacking Paul from the left.

Douthat says that this represents a scrambling of Bush-era categories, but it is more accurate to see it as a continuation of the old argument between traditional conservatives and neocons that the latter are a faction representing the left wing of the Republican coalition. There is nothing strange about small-government conservatives attacking Giuliani-like demagoguery on national security in these terms. What is different from the Bush era is that Giuliani-like demagoguery is no longer guaranteed to be a crowd-pleaser, and as Giuliani learned in 2008 it is not enough by itself to make up for other political weaknesses.

Christie’s national security rhetoric is best understood as confirmation that he is the candidate of the people that thought Giuliani was a competitive and credible presidential candidate. Many of the people urging Christie to run in 2012 were former Giuliani backers, and Christie seems well-suited to represent the small constituency that combines hawkishness and security state authoritarianism with more moderate or liberal views on some at least some domestic issues. It is not a constituency that will propel a politician to a presidential nomination, but it could ensure a devoted club of admirers among hawkish editorial writers and columnists.

Douthat makes a good point that realists served as a mediating force inside the Republican coalition, but this also helps explain why there is so little incentive for any ambitious politician to stake out position as a realist. As Hagel, Lugar, Huntsman, and others have shown us in recent years, Republicans win few friends and earn a lot of enemies by adopting this position. Non-interventionists won’t do much on their behalf because the realist internationalists are mostly content with the current U.S. role in the world, and neoconservatives and other hard-liners know that they can always find someone more willing to echo their arguments. Since there are no incentives to be a realist politician in the modern GOP, it is not surprising that no politicians speak for that tradition anymore.