From the Robbins column (Link supplied by Ebbie, above):

...the bottom of the class tends to produce a different kind of leader than the top. Those who wind up at the foot are often there by choice. They could do better if they studied, but they would rather trade class ranking for other pursuits. They tend to be the risk takers, the innovators, usually very well liked and in their own way driven. They know how to get into trouble, and more importantly how to get out of it. They also tend to have more than their share of luck.

Not that I'm arguing in favor of McCain as a candidiate in this election, but I agree that college grades don't mean much in the long run, except for those pursuing an academic career.

Of course, I'm prejudiced, as a lifelong underachiever myself.

Incidentally, George W. Bush was not the only C-student with a Yale degree to run in the last election. John Kerry's grades at that same insitution were no better than W's, even though he's obviously more articulate and possessed of superior critical thinking skills.