I think the U.S. is just an especially easy place to send a deep cover agent. It has a high standard of living so it's easier to recruit someone to be willing

I think the U.S. is just an especially easy place to send a deep cover agent. It has a high standard of living so it's easier to recruit someone to be willing to live here for long periods of time. It's not uncommon for someone to have a social circle made up entirely of people they've only known a few years. This seems to be much less the case in other places in the world, especially Russia. It's much more culturally heterogenous so it's easier for someone to blend in.