To all intents and purposes, the USA are an island. They have just two land borders with neighbours they have somewhat acceptable relations with. I think the r

To all intents and purposes, the USA are an island. They have just two land borders with neighbours they have somewhat acceptable relations with. I think the real issue they have is the unwillingness to cooperate with the other two measures: lockdowns (clashes with "freedom", at least temporarily) to reduce the number of cases to a range where they can be contact traced and then to allow contact tracing (I would guess this is because of a lack of trust in the government) to actually find people that might become infectious before they actually do. BTW "Just wearing masks" is not the solution but part of it.