The oddity of the emerging GOP presidential field is that it’s dominated by candidates — John McCain, Rudy Giuliani, Mitt Romney — who are, in one way or another, importantly unorthodox conservatives. Consequently, they need to hew very closely to hawk dogma in national security policy to prove their bona fides even at the moment where political support for the hawkish position is collapsing. Sam Brownback, a distinctly second-tier contender but one who benefits from being a committed social conservative with standard conservative economic views, is taking the chance to be the exception and resist the urge to surge. Ross Douthat comments as do Andrew Sullivan and (with bonus analysis!) Noam Scheiber who indicates that a pretty large number of social conservatives are anti-surge.
Of course, the Republican dove we liberals want to see is Chuck Hagel, but for a whole bunch of reasons Brownback is a more likely contender. The only thing I would add to this analysis is that, as best I can tell, ever since the war began in March 2003 it’s been the case that any given dovish position looks better and better as time goes on. When thinking about positioning yourself for primaries that won’t be held until a year or more from now, it’s worth keeping in mind that things will almost certainly look worse 9–15 months from now than they do today.