What did Donald Trump do today?

He had this exchange with Panamanian president Juan Carlos Varela.

TRUMP: The Panama Canal is doing quite well. I think we did a good job building it, right — a very good job. 

VARELA: Yeah, a hundred years ago.

Who cares?

• A president who cannot get more than eleven seconds into a public appearance with a nation's leader without free-associating is not doing the job he was elected to do.

• Nobody will ever assume a president is just playing dumb.

• Thirty seconds of preparation, if Trump were able to do it, would have avoided this.