Would NATO Actually do Anything if Trump Starts Invading Canada/Greenland?

The US remains the strongest country in the world and west is so reliant on the US right now. Who would want to fight the US if they ever invade a fellow NATO country and invoke article 5? Would anyone actually try to help Canada/Greenland militarily?

Expulsion from NATO and some sanctions seems like the most anyone would possibly do and Trump wants to be out of NATO. Especially with Russian aggression (and cancelled trade) on the other side isn't it even more likely NATO wouldn't do much to stop the US?