Trump blames Canada and the EU because the US has a "trade deficit" with them, meaning Americans like to buy goods and services from Canada and the EU. When asked what he needs to do to drop the tariffs, Trump says, "Let them balance trade."

He blames other countries because Americans are rich and like to shop.

To "balance" trade with the US, countries should ban their exporters from exporting to the US. Thus, they would forcefully reduce the American trade deficit. This amounts to the same as Trump's tariffs, so there's no point pandering to him.

Now all countries affected by Trump's tariffs should sign a joint free trade agreement, so that exports that were intended for the USA are redirected to other countries. The US is the richest market, but when all the others are united, the US will remain isolated. Thus, the EU and Canada would prosper, and the USA would stagnate in isolation.