During the debate, Donald Trump basically showed that he has no real idea of what judges do at all. Here he is, trying to tangle with Ted Cruz, bizarrely claiming that judges “sign bills.” Like they’re the President or Governors or something.

Trump: Now, Ted’s been very critical, I have a sister, who is a brilliant, [crosstalk] excuse me, she’s a brilliant judge. He’s been criticizing… he’s been criticizing my sister for signing a certain billYou know who else signed that bill? Justice Samuel Alito, a very conservative member of the Supreme Court, with my sister signed that bill. So, I think that maybe we should get a little bit of an apology from Ted, what do you think?

This is not “Trump isn’t a politician,” this is “Trump doesn’t understand Civics 101.” But what’s always interesting to me is to watch the candidates and their surrogates in the post-debate coverage, when their guard is let down a little bit. In this case, Trump was (irrationally) slamming Cruz again for John Roberts’ existence, and John King asked him, “How would you prevent the same thing from happening?” In other words, you’re being so critical of Ted Cruz, how would you make sure you didn’t repeat that mistake?

Trump’s answer was incredible. He said, basically, I have no idea. Watch:

JOHN KING: But what would President Trump do to make sure that doesn’t happen? What would you ask [of your potential judicial nominees]?

TRUMP: I would wanna see scholars, but I think more than my asking, I would go on references of other people that I respect. Because that is not necessarily my world. I’m very much into the world of legal and legality. But, that is not my world, so I would go to people that I have great respect for and say, “Who do you recommend?”

This is a pretty stunning admission from Trump – even setting aside the question of what “I’m very much into the world of legal and legality” even means. What Trump is saying here is that he, personally, has no idea whatsoever what he would do. He has no idea what questions he might ask of a judge.

This is not a guy who can be trusted to not repeat the mistakes that gave us David Souter. By his own admission he has literally no idea what he’s doing when it comes to judicial nominations. Quite frankly, as he demonstrated in the debate, he does not even know what judges do. And this is someone you want picking the replacement for Scalia?