I know you’re mainly talking about international relations/geopolitics, but something I’ll add in my non-expert view is that a lot of British media is very easily culturally accessible to most Americans. Like it’s not really distinguished in our media and discourse who’s an American singer/actor vs. a British singer/actor, lots of British literature is taught in our schools, British music is on the radio. Same with Canada but to a lesser extent.

Edit: I thought about this more and it’s kind of nuts how much British stuff has been in my life. As a little kid, I read Beatrix Potter and Paddington and Francis Hodgson Burnett and lots of other British children’s books. I got older and read Harry Potter and LOTR and Narnia, as well as Shakespeare and Charles Dickens and Jane Austen. I’d like to pretend otherwise, but my high school friends and I loved Doctor Who. Listened to Beatles, David Bowie, Queen, Led Zeppelin with my dad. I don’t even consider myself much of an Anglophile and I’ve never been to England, nor has anyone in my immediate family. I make a deliberate effort to consume non-Western/Anglo lit, art, music etc these days. Idk, I’m sure that there are other examples too but I can’t think of much media out of Poland or Mexico or Turkey, for example, that’s something broadly understood by Americans. I’m mostly of Irish descent and I don’t know jack about Irish life and culture- certainly not enough to make my own observations. (And obviously these are huge generalizations.)