I'm curious about one aspect of the Golden Dome:

Don't we need Canada to agree to participate in it?

I mean, Canada's already the location of nearly all of the Northern Warning System missile detection network - all those radar are mostly along Canada's northern coats. Presumably the Golden Dome will have missile detection that either piggy-backs off the NWS and launches counter-missiles from there, or will involve replacing those systems with new ones in the same location.

If Greenland's going to be part of the Golden Dome, then the dome has to go pretty far north. Greenland's entirely north of Canada, after all - Greenland would be unnecessary for the Golden Dome if the northern line of the Golden Dome is on U.S. soil, rather than Canadian territory.

Which begs the question - why is Donald Trump getting into a pissing match with Canada? If the Golden Dome - and access to/defense in the Arctic more broadly - is so fundamentally important to Trump, then he's going to need Canada's help with all that. Why on earth is he stoking conflict with them, when they're integral to something he thinks is that important?