"Suppose I were a politician; suppose I were an idiot. But- I repeat myself" (Mencken, I think)
And my favorite: Winston Churchill was seated across from an extremely plain woman at a dinner party. He peered over at her and said "Madam, you are by far the ugliest woman I have ever sat at dinner with.."
Outraged, she said, "Mr. Churchill! You, sir, are drunk!"
"Yes, madam," Churchill said. "But in the morning I will be sober, and you will STILL be ugly..."