My underlying belief is that this is all about Trump accepting longstanding American policy, relying on collective defence, but getting frustrated that its allies do not perceive threats on the same terms America does. America discovered how expensive it is to go it alone. And how thankless that route is. But the collective route demands that the collecive works to the mutual satisfaction of all members.
Trump is doing the other thing. US politicians failed to get the results they wanted by being polite. Trump is impolite.
The difference between Trump and a politician is that politicians care what other people think. Trump grew up on Page Six of the New York Post, in New York society, in the world of developers, casinos, gamblers and entertainers. With money. He doesn't give a damn what other people think. He does love the show though,
The decades-long friendship of two men who never especially changed.
www.nytimes.com