JOHN HEILEMANN (CO-HOST): What do you think that the Republican nominee has to do tonight?

MARK HALPERIN (CO-HOST): One big macro thing: act presidential. Act calm, cool, and collected the way he did at the press conference in Mexico with the Mexican president. The way he did in a townhall meeting he did with his family with CNN. If he is simply calm, and cool, and reserved, and gracious, I think he will at least tie this debate. If he just does that one thing.

HEILEMANN: Right, I obviously agree with you that's an important factor. I also think though, because of the fact that so many Americans -- and so many voters -- believe that Trump either is not either smart enough or knowledgeable enough about the world. In addition to the temperament question you're addressing, I think he needs to show some substantive heft here tonight, and not make mistakes. He can't, I think, make big blunders on substance. I think he can't lose his cool. I think he's got to keep it together, but also show us more than just that he can be calm and cool. I think he's got to show that he's intellectually up to the task of being Commander-in-Chief.

Previously:

The Bar Gets Lower: Media Reinforce Double Standard For Trump Ahead Of First Debate

Media Finally Admit The Bar Is Lower For Trump. But Can They Fix It?

Bloomberg's With All Due Respect Highlights Media's Insistence On Lowering Bar For Trump