I would argue that Trump IS smart, but not in the traditionally sense. He is a brilliant politician that seamlessly weaves lies and misleading statements into his speeches, and no one that support him cares.

Everything he does is cold and calculated— from not divesting from his businesses like every president before him, to hirinf his family in viollation of the nepotism law.

Why does he do things like trying to get dirt on Biden from Zelenskyy to calling the SOS in Georgia to change the election results to stealing top secret documents? Because he feels with 99% certainty taht he will never be held accountable.

There is a fairly good chance that he will never be held accountable for all the crimes he's commited in plain site. Even with today's appointment of a special counsel, it's going to be very hard not to get at least one Trumper on a jury that will not let him off regardless of his actual guilt.