Why in blazes would he ever want to do that?
There are any number of qualified Democrats suitable for the position - which is entirely his right to appoint. If Obama sweeps to power, as is likely, carrying with him Congressional victories on his coat-tails, why would he take that as anything less than a mandate to change direction on foreign policy? Certainly Obama wants to set up a Lincoln-esque team of rivals dynamic in his administration, but there is no good reason to concede to the Republicans the DS portfolio, from a position of weakness implicitly affirming the false frames of the last decades about Republican toughness on defence. Obama will be looking to overturn that. At best, Gates will remain SD for transition.
Also, if anything, McCain’s views on foreign policy are further to the right than Bush’s first-term, though not his second, as we can gauge by the coterie of neo-conservative war cheerleaders he has surrounded himself with, and his erratic hawkish positions on kicking Russia out of the G8, escalating force against Iran and establishing a “League of Democracies” to supplement the U.N.
Then there is also the point that there are plenty of other Republicans who at least support the Democratic foreign policy and security platform, either out of Realpolitik or a sense of internationalism; I’m talking about people like Gates, Baker, Hagel, and even Powell - who are all better candidates.
Why McCain other than some weird idea of him deserving a consolation prize for some reason?