This scenario is borderline impossible but in the event of it happening it'd be open civil war. Any americans with the means to leave do so. We're talking it gets to the point where we see Mint is in Bogota, BRTD is in Helsinki, Everett in Tokyo, Phil in Naples, myself joining killerpollo in Chihuahua, Xahar in Dhaka and The likes of blubb/duke/StatesRights going to South Africa.
Remember that it's 2008 and not 1988. Why would any of those guys move to a country where whites are a minority and which is ruled by black socialists (and I'm talking about actual socialists)?
Joining a boer commune on the veldt and forgetting about the rest of the world. Chile is another destination of american cons.