[whatshisface]

Believe it or not, the US is still a republic with diffuse power. While the president can have a whim to do something, the rest of the system still needs a reason to allow it. I don't think explanations that rely on total alignment with an individual personality are complete.

Preparing for a war and preparing to threaten it with good credibility are exactly the same thing. That is what the US and the USSR were doing when the end of life on Earth (or at least all life in New York or Moscow) was regularly bluffed against. In the modern world deliberate wars are quite rare, at least as the theory goes they are failed attempts at bluffing. Obviously no country would start a war without first trying to threaten it unless their intent was genocidal.

After the 1000th time of threatening the advisors will start to say, "we will look weak if it doesn't happen."