Despite his aversion to the religious right, Sullivan has been supporting mostly conservative Republican positions for quite a few years, with the exception of his stand on gay marriage and homosexuality in general. He was a vocal supporter of George Bush in 2000.
Sullivan is an Oakeshott conservative, and did his doctoral dissertation on him, conducting some twenty years ago, as I understand it, one of the last interviews the old philosopher ever sat down for.
Even during his brief editorship of The New Republic Sullivan was known for pushing that publication to the right. And Howell Raines declared a few years back, in so many words, that Sullivan's work was too conservative for The New York Times. Temperamentally, intellectually and in most every other way, Sullivan, a practicing Roman Catholic, is a foundationalist, and thus a man of the right on today's political spectrum.