McCain thinks the recent conflict between Russia and Georgia was "the first probably serious crisis internationally since the end of the Cold War." He thinks Iraq and Pakistan share a border. He believes Czechoslovakia is still a country. He’s been confused about the difference between Sudan and Somalia. He’s been confused about whether he wants more U.S. troops in Afghanistan, more NATO troops in Afghanistan, or both. He’s been confused about how many U.S. troops are in Iraq. He's been confused about whether the U.S. can maintain a long-term presence in Iraq. He’s been confused about Iran’s relationship with al Qaeda. He's been confused about the difference between Sunni and Shi'ia. McCain, following a recent trip to Germany, even referred to "President Putin of Germany." All of this incoherence on his signature issue.
Here’s the thing. Any of those individually is just a slip. Put together they could still just be one (or 11) of those things. But what if they’re not? What if McCain really is fading away, something that wouldn’t be too surprising for any 72 year old? At what point would the Republicans (or Democrats, in a similar situation) say “You know what, our candidate was a brilliant man, but time has passed and it’s become clear that he’s just not up to the job”? My guess is no earlier than November 8th.