"a man with almost unlimited, focused energy spearhead..." It's obvious Smith's letter is entirely tongue-in-cheek. Haven't you seen Trump lumber his 6-foot-3, 236 pound frame down the few stairs from Marine One? The guy is borderline obese and no wonder, he regularly gobbles down McDonalds and other junk food.
Analyses of Trump's vocabulary suggest he's experiencing cognitive decline--he's the oldest President ever, and it shows. 
"You know what uranium is, right? This thing called nuclear weapons, and other things. like lots of things are done with uranium, including some bad things. Nobody talks about that. I didn't do anything for Russia. I've done nothing for Russia."
6 variances on the word "thing" in the span of 15 or so seconds. Okay, so his cognitive decline is not as far along as Reagan was, nevertheless, Republican voters' preferences for candidates suffering from cognitive decline is notable.