I don't get it*

While suturing a cut on the hand of a 75-year-old rancher whose hand was caught in the gate while working cattle, the doctor struck up a conversation with the old man. Eventually, the topic got around to Sarah Palin and her bid.

The old rancher said, "Well, ya know, Palin is a 'post turtle.' "

Not being familiar with the term, the doctor asked him what a 'post turtle' was.

The old rancher said, "When you're driving down a country road and you come across a fence post with a turtle balanced on top, that's a 'post turtle.' " The old rancher saw the puzzled look on the doctor's face, so he continued to explain. "You know she didn't get up there by herself, she doesn't belong up there, and she doesn't know what to do while she's up there; so you just wonder what kind of dummy put her up there to begin with."

*The blog title is sarcasm. Since no one seems to know when I'm being sarcastic, I'll go ahead and try to head off a bunch of comments where people try to explain the idea behind the joke...