GWB as "post turtle"

A doctor and an old Texas rancher were talking about George W. Bush being in the White House. The old Texan said, "Well, ya know, Bush 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 man saw a puzzled look on the doctor's face, so he continued to explain, "You know he didn't get there by himself, he doesn't belong there, he doesn't know what to do while he's up there, and you just want to help the dumb bastard get down."