Christopher Hitchens type New Atheist liberal internationalist who felt the Christian Right had too much power and voted for Kerry. Switched back to the Republicans because of taxes and perceived Dem weakness on foreign policy. Incidentally, Leonard Peikoff (Ayn Rand's designated successor) was of this view and endorsed Kerry in 2004, before not endorsing anyone in 2008 and then Romney in 2012.
It would make more sense for this person to be a Gore ‘00-Bush ‘04 voter though, because if anything, Bush ran as the less interventionist candidate in 2000.