On trade imbalances: Trump expects Canada, a country of 40 Million people, to buy as much goods from the USA, a country of 300+ Million people. And if you subtract the oil that the USA buys from Canada, Canada has a trade SURPLUS with the USA. That is, apart from selling oil to the USA, Canada buys MORE from the USA than the USA buys from Canada, a country roughly one tenth the size.
This trade war isn't about righting trade imbalances. It's about the USA exerting leverage over countries that it can get away with. Just like a Mafia Don.
Or to quote a crude summary from Peaky Blinders: "Big $ucks small".
That's the philosophy of the Trump Administration in a nutshell.