With POD of later than 1900, make USA Join Commonwealth of Nations.
One two conditions:
No ASB and USA has to stay a republic.
One two conditions:
No ASB and USA has to stay a republic.
https://en.wikipedia.org/wiki/London_DeclarationI would highly find it entirely impossible for it to do so if it remained a republic and with ASB magic. Seriously.
Still wouldn't be possible for the US even if it stayed a Republic. The politics of the US would literally would prevent it from joining the Commonwealth of Nations especially the formerly conservative Democratic Party.
I think Queen as head of the Commonwealth would make it symbolically very difficult for the United States regardless of Britain's relative power.
Well, if places like Kenya, whose founders within living memory a war against the Empire, can stomach a Queen-led Commonwealth, it possibly might not be too bitter a pill for the Yanks to swallow.
Though perhaps Americans are more wrapped up in their identity as a republic than are various third-world arrivistes? Plus, I'm assuming the third-world Commonwealth states get some sort of financial or at least material benefit from being members, which probably helps the medicine go down in at least a slightly more delightful way.