Interesting, but there is some irony here.
A few months ago he was telling the more right-wing members of the Republican establishment to cease fire over their criticism of McCain.
http://www.nytimes.com/2008/02/19/op...19buckley.html
"It may strike some conservatives today as odd, if not absurd, to see John McCain being subjected to an auto-da-fé conducted by such Torquemadas of the right as Rush Limbaugh, Ann Coulter, Sean Hannity."
"In response, let me offer a thoughtful, considered, carefully worded comment: Would you all please just...shut...up?"
Of course in politics you can change your mind, but for him to do a complete 180 in a few months time and endorse Obama, and really equally ironic that the Limbaugh's of the world have jumped behind McCain.