This doesn't show much of anything. The first lady seems confused at the question, and the second guy there's an EDIT between the question and the response. They were probably either too polite to correct the guy, weren't paying attention to the name, or became unsure of their own knowledge in the midst of answering a bunch of rapid-fire questions. Of course, Bush is a maroon, but he probably knew the PM because they were making him study his flash cards.

Sorry, this Mercer's way to make Americans look "stupid" is just lame tricks. If you go up to the man on the street and shove a microphone in his face and ask him if the president on the 5 dollar bill should be changed from "Franklin" to "Reagan", he'd probably give a yes or no response because he's mentally focusing on the Reagan part and changing the currency -- even if he knew Franklin was never president, and wasn't on the Fiver. And in the event guy realizes the questioner was wrong, he'd probably be too polite to correct him.

Colbert, OTOH, gives people lots and lots of rope to hang themselves. A smart person will look smart, and a dumb person will make a fool of themselves.

But this video is interesting because it does indeed look like Bush has had a nosejob since those days, or he's been chasing parked cars.