Michael Steel, former senior adviser to Jeb Bush:

[Trump] managed to come up with words that sort of formed sentences, but [when] asked a very specific policy-based question, an important one, he had no response. He managed to string together words. He never gets that deer-in-the-headlights look, even when he clearly does not know what he’s talking about. I don’t remember him ever being flummoxed.

At the North Charleston debate, he had an answer on Boeing and trade jobs that showed some preparation [Boeing is a major employer in South Carolina and there have been tensions over an attempt to unionize the workers. Trump said in the debate that these jobs could move to China.] It’s an obvious attack given the huge Boeing plant right up the road from that venue, that these are good-paying SC jobs that you’re essentially going to throw away. And he had a response about Boeing now having to do manufacturing in China. And what he said wasn’t accurate, but it had a kernel of truth to it and was based on a relatively recent news story, which suggested to me he was doing some kind of traditional debate prep, in the sense that that was an obvious attack given the location and he had a factual-ish response.

Secretary Clinton needs to be prepared for Trump to say things that are wildly factually inaccurate. I think she needs to be prepared for the fact that he is most dangerous when he is on the defensive. If she feels like she lands a blow or is scoring points, that’s when they need to be most worried about him launching a personal attack or saying something outlandish.

[A debate moderator needs to have] a big personality, because in addition to being completely fluid on the facts, [Trump’s] perfectly happy to walk over you. He’s got a lot of skills of an entertainer, of a television personality, that make it very difficult for traditional candidates to debate him.