The distinction between "is" and "was" was seized on by the commentariat when Clinton told Jim Lehrer of PBS right after the Lewinsky story broke, "There is no improper relationship." Chatterbox confesses that at the time he thought all these beltway domes were hyperanalyzing, and in need of a little fresh air. But it turns out they were right: Bill Clinton really is a guy who's willing to think carefully about "what the meaning of the word 'is' is." This is way beyond slick. Perhaps we should start calling him, "Existential Willie."
http://www.slate.com/articles/news_and_politics/chatterbox/1998/09/bill_clinton_and_the_meaning_of_is.html