2/28/07: McCain Announces on Letterman: Sen. John McCain, R-Ariz., tells David Letterman he plans to announce a second presidential bid in the coming months. "The last we were on this program ... You asked me if I would come back on this show if I was going to announce," McCain said on "The Late Show with David Letterman." "I am announcing that I will be a candidate for president of the United States." The Arizona Republican's official announcement came on April 25, 2007, at a rally in Portsmouth, N.H .
(CBS/AP Photo)