This is true. A President doesn't work in a vacuum. He's not a dictator. He's a cog in the machine of government and has to fight and wheedle and manoeuvre just like everyone else. And if he's a weak man- George W Bush for instance- he's liable to be pressured and influenced and manipulated by those around him. Besides the government of the USA is a vast, sprawling thing- and no single person could possibly comprehend and control it all. This may be paranoia talking, but I've read that a President's security clearance only goes so far up the ladder- and there are parts of government- the whole black ops dimension- to which he has absolutely no access.