You would be surprised about how many things we still don't know in Biology. But we do know a few things... for example that European and American polecats are

You would be surprised about how many things we still don't know in Biology. But we do know a few things... for example that European and American polecats are mammals in the same genus and close genetically. So close that both are susceptible to the same diseases and in particular to the same viruses. How do I know that? Because I'm interested in pathology of vertebrates. We know also that the American polecat went extinct, and that diseases played a main role in that. Check the bibliography. Are you following me? So when you say that there was "not any measurable effect". Yes, in fact there is a clear perfectly observable effect. The closest carnivore to European polecats went extinct in the wild. Why? > benefit of federalism in serving as 'the laboratories of democracy': I refuse to enter in political stupidity molasses. We are talking about nature problems here.