Winter in D.C.
The president wakes up and wanders over to the window to look out over a white blanket of newly fallen snow. He's about to turn away when he happens to look straight down. On the lawn beneath the window, someone has written, "The President Sucks!" in big yellow letters in the snow.
He hollers for a Secret Service agent who rushes in from the hall. He shows him the message and demands the person responsible be found immediately.
Later in the day agents come into the president's office, carrying some papers and looking very nervous.
"Mr. President, we've analyzed the message. We've determined that the message was written in urine, and we've matched a sample."
"Sir, the urine belongs to the vice president."
The president is outraged. "I knew it! You get that son of a bitch in here this instant." But the agents are oddly frozen in place.
"Well, what are you waiting for?"
"Uh sir, before we get the vice-president, there's something you should know. The urine is his, but the handwriting...
...is the first lady's.