If you’ve ever watched a congressional hearing featuring Sen. John McCain (R-Ariz.) in a bad mood, you know the Arizona Republican can get pretty quarrelsome with witnesses who annoy him in some way.

Take today, for example.

During a Senate Homeland Security Committee hearing on the ongoing border crisis, McCain was outraged by a recent memo saying visitors to detention facilities had to check cell phones with cameras. The senator, outraged, demanded that Thomas Winkowski, a Deputy Assistant Secretary for U.S. Immigration and Customs Enforcement, explain himself (thanks to my colleague Nazanin Rafsanjani for the heads-up).

McCAIN: Mr. Winkowski, I’ve been representing the state of Arizona for many years and I’ve never seen anything like your instructions to signed by your name, ‘interim protocol for visitations and tours to CBP detention facilities.’ Are you telling me, when I visit a detention facility that I can’t bring a cellphone with me? Are you saying that? A United States Senator visiting a facility. These are the instructions that you have signed. Is that what you’re saying? WINKOWSKI: That the visitors can’t bring cell…? McCAIN: Visiting congressional deleg, uh, member of Congress. WINKOWSKI: I don’t recall saying that. What I recall…. McCAIN: Let me provide you with a copy. It says see distribution. R. Gil Kerlikowske, Commissioner interim, protocol for visitations and tours to CBP detention facilities. You didn’t see your own memo?

You might have noticed the problem. R. Gil Kerlikowske wrote the memo. McCain was yelling at Thomas Winkowski.

For the record, R. Gil Kerlikowske and Thomas Winkowski are not the same person. Their names may rhyme, but I’m afraid that doesn’t much matter. Senators in high dudgeon should probably get these details right before upbraiding a witness publicly.

In any case, R. Gil Kerlikowske was sitting next to Thomas Winkowski, and so McCain’s bellicose line of questioning continued after the identity question was straightened out.

McCAIN: Am I allowed to bring a cell phone with me when I go onto a facility in Nogales Arizona? KERLIKOWSKE: Not to take photographs senator. McCAIN: I am not allowed to take photographs? Why not? Why not? Why am I not allowed to do that? KERLIKOWSKE: That children have a right to privacy and that’s why we’re not having their faces shown… McCAIN: I may want to take a photo of something else!

Kerlikowske, the commissioner of U.S. Customs and Border Protection, stayed admirably calm in the face of McCain’s angry questions, patiently trying to explain the rationale for the current policy. Officials are trying to look out for the children’s privacy, so they’re not allowing people to bring cameras into facilities.

If McCain wants to take pictures of something else, Customs and Border Protection officials will arrange to let him take pictures of whatever he wants. If McCain wants to talk to people at the facilities, Customs and Border Protection officials will arrange conversations with whomever McCain wishes to meet.

That, apparently, wasn’t quite good enough for McCain, who demanded a new memo.