President Donald Trump's cognitive decline was on full display this week, longtime Beltway reporter John Heilemann told MS NOW's Nicolle Wallace on "Deadline: White House" — and it's obvious when you compare his demeanor to a few years ago.

You know, look, they asked him the other day on the airplane, on Air Force One, why he took an MRI, and he said he didn't know," said Heilemann. "If getting the camera-person-TV thing right is acing it, not knowing why you took an MRI is flunking it. I'm not sure what to make of any of those things, but it's totally clear and has been for some time."

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"This is not the first time I've said this, but if you look over the course of the last 10 years, we've had Donald Trump in our lives, you can measure the decline in his mental acuity," said Heilemann. "You can measure it by looking at the interviews he gave in 2015 and 2016, looking at them in 2020. Look at them now. His vocabulary has reduced dramatically. The complexity of the words that he uses. He rarely uses multisyllabic words anymore. He says the same words over and over and over again. This is — you know, these are people who do linguistic analysis and go and look at those things. If you go back and look at Trump's interviews from 2016, he was never a genius, but he could conduct or have a real conversation with the Wall Street Journal editorial board about trade policy that didn't seem the way he sounds."

"For him to go out there and give that speech at that level of incoherence and political, politically suicidal impulses, there's not a Republican in the country who's going to be like, yeah, I want President Trump in my district during this midterm year," he added. "He's going to be nothing but toxic for all of them."

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