Invasion of the USA

A Navy destroyer stops four Mexicans in a row boat, rowing towards California.

"The captain gets on the loud hailer and shouts, "Ahoy, small craft, where are you heading?"

One of the Mexicans stands up and shouts, "We are invading the United States!"

The crew of the destroyer all start laughing and when the captain finally stops laughing, he gets back on the loud hailer and says, "Just the four of you?"

The Mexican stands up again and shouts, "No, we're the last four, the rest are already there!"