The constitution is old and not democratic.
Russia, Turkey, Phillipines, Belarus, Nicaragua, etc, etc.
Presidential republics are a disaster waiting the right people to break them.
Less than half of the people who bothered to vote actually picked the guy.
I even believe that a non-trivial number of those folks actually believed their own rhetoric about America first, no wars, etc. But their commitment to one man is stronger than their commitment to ideals, and so here we are.