Ross thinks it was in his short form:

His artfully recondite style worked best in small, explosive passages.

The smaller the better. I wonder if Buckley would have been a blogger in another era. I know we shouldn't speak ill of the dead - but am I the only person who found Buckley close to unreadable a lot of the time? I never read his fiction, but his nonfiction was packed the endless sentences, ridiculously long words, and meaning that sometimes took several reads to excavate. I don't know how many times I finished a Buckley column with the thought: what on earth was he trying to say? But then, my gold standard for prose style is Orwell. Never use a long word when a short one will do is not exactly advice Buckley followed.