From a New Yorker profile of Al Gore:
Gore remains engaged, serious, credentialled. It is still easy to imagine him as a good, if unloved, President. And yet one trait persists—and it is a trait that he shares with George W. Bush. He is extremely reluctant to admit a mistake, even a small one. Midway through our talks in Nashville, I asked him what was the biggest mistake he had ever made in politics. He paused, made false starts, paused again, and recalled that in the campaign four years ago he had a prepared response for just such a question. But he couldn’t remember what it was.I suspect that this is true of most politicians.