Pathogens do not care about civil rights.
I doubt Ebola is it, but sooner or later we will be hit with a highly contagious and lethal disease. The only way to stop it before it gets away from us is immediate and ruthless application of well-known public health measures. Which we won't be able to do because people won't trust, perhaps with good reason, the health authorities who will be needed to coordinate this effort. Such an effort, by definition, must be rigorously and centrally controlled, which means the fedreral government.
So it will get away from us and thousands or millions of Americans will die.
Hence, medical martial law.