It has become extremely normal for politicians to say something untrue or irretrievably dumb on purpose, in order to create a politically beneficial controversy.

A politician does this to spread disinformation. The goal is to disinform the credulous, not educate the curious. It is also a way to set the agenda. If the public debate is on turf you don’t like, engage in this behavior and the conversation changes. It is better to be called a liar or a fool on your turf, than to be a true man on your opponent’s turf. Once your allies hear glass breaking on turf they care about, they run and rally. They don’t get the blood up for public conversations about issues the other team cares about.  Your supporters don’t care about the facts of the case or that they are rallying to a cause that makes no sense. They are keen to mock, oppose and thwart the other side. So, when spirits are at a low ebb, trip the boy in the hallway. This puts some color into the faces of your mates. You don’t mind when the hall monitor arrives to sanction you, because you’re just happy to have the home team in a better mood.

This is not a new phenomenon. There is a possibly apocryphal story of Lyndon Johnson who accused an opponent of having amorous relations with pigs. Johnson’s aide told the candidate he couldn’t make such a scandalous charge because it was not true. Johnson said, “I just want to hear him deny it.”

But it is much more widespread now.

I talk about the challenge of facing this as the host of Face the Nation in an interview I did many years ago with Glenn Thrush.