Remember, just three years ago, when everybody ridiculed Arnold Schwarzenegger for announcing his candidacy for governor of California on The Tonight Show? Times change, quickly. John McCain is announcing his candidacy for president Wednesday night on David Letterman's show. “The last time we were on this program -- I’m sure you remember everything very clearly that we say -- but you asked me if I would come back on this show if I was going to announce,” McCain told Letterman at this afternoon's taping. “I am announcing that I will be a candidate for president of the United States.” No word yet on whether Dave was as impressed as the time Drew Barrymore flashed her boobs at him.