I don't think he's stupid. Stupid for the things he has done that we do not agree with, perhaps, but not stupid in the sense of not intelligent.
Sure he doesn't posess a sharp tongue, or fine motorics, or mimics, but that doesn't say anything about how intelligent you really are. The republican party is a very large organisation and reaching the top there means you have to be prominent and win pre-elections, which have mini-election campaigns by themselves. Anyone remember Howard Dean and "The Scream"? I can assure you the whole process is anything but easy.
And he does have power, the US President is definitely not merely a "figurhead" for policies made by other people.
Pubic: Agreed, because you don't support his cause. However the "terrorists" in Guatanamo didn't go to another country, they have their enemies right at home. What if it was an occupied nation during WW2, and someone of the resistance suicide-bombing a bunch of Germans? Would he be a hero? Does it matter if Afghanis blow up Russians or Americans?
DeZmond: Nice one with the "Totalitarian police state in four easy steps for dummy presidents" guide. Hitler would be proud of you. You only forgot mass censorship and indoctrination. Something frantic like the Red Scare would be ideal.