... fairly few of the really damaging things he said in this campaign were in the debates. They tended to be at rallies or in interviews. Put simply, Trump wasn't as crazy or unhinged in debates as people seem to remember. So if we're expecting him to come in trash talking and angry I think we may be surprised, at least at first.What Marshall thinks will really get Trump in trouble will be the need to talk about issues at length in what will be his first two-person debate. As Marshall sees it, we'll all know what a simpleton Trump is as soon as he starts having exchanges like this one from the September 7 national security forum:

Marshall thinks this is self-evidently awful.
As I said at the time: I think this exchange is pretty obvious for people in a way that transcends politics and ideology. Trump is the kid telling the teacher the dog ate his homework. Then the teacher points out he has no dog. But he's not going to apologize or come clean. He's just going to keep talking.But that's not what I take away from it. I'm imagining how this must have gone over with voters -- not just Trump supporters, but persuadable voters in the middle. Most Americans aren't politics junkies and aren't particularly sophisticated about foreign policy. And, maddeningly, far too many Americans think Trump is honest, which means they think he's arguing in good faith, rather than slinging bullshit.
So what did these voters see? They saw a guy saying he doesn't want to tip his hand on ISIS because he wants ISIS to find him "unpredictable." (Presidential!) They saw him saying he'd respectfully turn to generals for advice about ISIS. (Presidential!) They saw him say that, yes, he long ago devised his own plan for defeating ISIS. (Presidential!) But he wants to refine his plan by turning to those with military experience. (Presidential!)
That Trump is BS'ing us is obvious if you put all his statements together. But if you're a casual voter, every statement in isolation seems to pass the commander-in-chief test.
That's what I worry about: Trump finding enough platitudes, bumper-sticker slogans, and hollow boasts to fill up his half of a ninety-minute debate, and the press giving him a gentleman's C -- no, a gentleman's B-plus or A-minus -- because he was expected to do worse.