"Here’s what we can be fairly sure will happen in Monday’s presidential debate: Trump will lie repeatedly and grotesquely, on a variety of subjects. Meanwhile, Hillary Clinton might say a couple of untrue things. Or she might not. Here’s what we don’t know: Will the moderators step in when Mr. Trump delivers one of his well-known, often reiterated falsehoods? If he claims, yet again, to have opposed the Iraq war from the beginning — which he didn’t — will he be called on it? If he claims to have renounced birtherism years ago, will the moderators note that he was still at it just a few months ago? If he says one more time that America is the world’s most highly taxed country — which it isn’t — will anyone other than Mrs. Clinton say that it isn’t? And will media coverage after the debate convey the asymmetry of what went down?"