I mean define collapse; if it’s just “a general decline in coherence and ability to bring power to bear”, then marginal gains in control of fisheries and the great lakes, ability to control oil prices and exchange rates and the balance of profit in the cross-border auto parts industry

If the US-led trade regime starts to fray I could see them reorienting around post-EU Britain and maybe Australia/NZ, a Commonwealth bloc with enough capacity to patrol its own trade lanes

I do wonder in that neo-Empire scenario whether the centrality of Chinese money and expat/immigrants in Australia and Canada becomes a geopolitical issue

juciest case as America loses the ability to control its own territory in detail the border becomes a site of large-scale drug and gun smuggling, strengthening domestic gangs

or no wait maybe a wave of expatriates, or refugees, or something in between - well-fed types that couldnt pass the points system but apply for asylum? the canadians actively seek immigration but arctic seas and a whole continent give them buffer to pick and choose, seeing that challenged (while the housing issues scream even worse) would be interesting