Barack Obama was elected president in 2008 because he was not George W. Bush. In fact, he was elected because he was the furthest thing possible from Mr. Bush. On some level he knew this, which is why every time he got in trouble he'd say Bush's name. It's all his fault, you have no idea the mess I inherited. As long as Mr. Bush's memory was hovering like Boo Radley in the shadows, Mr. Obama would be OK.

This week something changed. George W. Bush is back, for the unveiling of his presidential library. His numbers are dramatically...