Well it gets more complex.
As by definition a Ford Focus, nah ANY Ford is American as Ford Mo Co is an American Auto maker with European works/factories and distributors.
The insurance company didn't like this.
So I said how about a Mercedes Benz M Class, they are built in the US. And MB is know merged with Chrysler.
Again the insurance company didn't like this either.
Another take would be somthing like a Triumph TR8, this was only made for the US market in LHD and not sold over here (a few TR7 V8's where), so I guess it's as much American as any other American car.
It could get silly, A Vauxhall Vectra, after all GM is an American auto maker and owns Vauxhall.
The insurance company eventually decided they had no idea how to define an American car