I'm under the impression that the relatively successful containment in the Democratic Republic of Congo (compared to the West African outbreak) is an illustration of the impact a prepared, functional public health system has on Ebola. Nigeria too.

I wouldn't be stunned by a delay in response due to "it can't happen here" chauvinism, but once enough people were taking it seriously I would expect the US public health system to be up to the challenge. Hopefully there would be little or no delay in treating it seriously, I'm just pointing to that as a likely contributor to the size of a potential outbreak.