No offense

Why do people say "No offense" right after or before saying something offensive? As in, "No offense, but [fill in offensive tirade here]"? Perhaps if I say, "No gravity" just before I leap from the top of the Empire State building, I'll be able to fly.

Toward Totalitarianism: Reading Your Mail

According to the New York Daily News, President Bush has claimed the authority to open and read Americans' mail without a warrant. This claim was made in a "signing statement" on December 20, 2006, contrary to existing law as well as the bill he was signing into law.