Donald Trump is incapable of doing the job of President of the United States.
This is true in myriad ways, of course. Per recent reports he is knowingly and openly communicating deeply personal information under surveillance by Russia and China in order to evade the eyes and ears of his own staff, but he is so profoundly ignorant of operational secrets that the national security apparatus barely cares if adversaries are listening in on him. He is obsessed with the poison of TV news, holds ugly pep rallies in lieu of working, uses blatant nepotism in his hiring practices, conducts national and international policy for his own personal profit, lies about all things large and small with giddy and reckless abandon, and ignores matters of importance while fretting over slights and trivialities. And none of that even touches the increasingly abhorrent economic, environmental and social policies of the modern Republican Party that Donald Trump now controls by right of conquest.