USA HAS a vested interest in that at the USA behest, Ukraine gave up its nuclear weapons and USA guaranteed its territorial integrity.

USA has a vested interest in keeping its promises to allies and other countries it made agreements with does it not?

Funny part about Canada is that our Free Trade Agreement (CUSMA) is due for re negotiation next year, and Trump only had to wait until that window opened.
Instead we have a trade war based on a pretext of National Border Security.

It will harm the US economy and Trump himself admits a recession is coming because of it...but he will take that as OK

So price hikes from tariffs, and a US recession as fired federal workers, no US agricultural sales to USAID and resulting farm job losses, and no us arms sales (job losses in the Military Industrial Complex)
swell the unemployment ranks.

If writing ever becomes work I think I'm going to have to stop