He doesn't mean it like that. He's referencing the tendency of other nations to grant citizenship to descendents of citizens. E.g., if my father were German, I'd have a better chance of acquiring German citizenship than if my most recently immigrated ancestors came to the U.S. circa 1840 (which for me happens to be the case).

I read it more to mean, a US citizen with highly attenuated ties to another country; after 3rd generation, you aren't likely to have immediate family overseas, &c. At least, I hope that's what was meant.

Yes, this is what I meant.