Max Bergmann says of John McCain's al-Qaeda/Iran mix-up:

That is not a gaffe. That is called believing something that isn't true. It is called being confused. And being confused about the differences between Shia and Sunni when claiming that you should be elected president of the United States on your foreign policy knowledge and experience, is simply not okay. This is a big deal.

Yes, it is a big deal, especially because, as Ezra Klein notes, "McCain has a fairly aggressive policy take on Iran and the long-time belief that they were an al Qaeda safeground may have contributed to his thinking." Quite so. Certainly the Iranian nuclear issue would look very different if I thought the Iranian government were training al-Qaeda operatives on a regular basis and working hand-in-glove with them in Iraq.