Is there any vaguely-homogenious 0.1% of America's population that could stand alone outside of American society, when you start requiring mega-scale social systems like a first-world legal system and military? I'm thinking "no".
Depends on the threat model. Settlers of the 19th century had a legal system and were mostly able to defend their settlements, though not to take on, say, the Japanese empire.
The Amish are probably able to put some kind of legal system together themselves, but their decided religious pacifism limits them to living under protection of others.
Is there any vaguely-homogenious 0.1% of America's population that could stand alone outside of American society, when you start requiring mega-scale social systems like a first-world legal system and military? I'm thinking "no".