...unfortunately their methods and many of the other things they get, is pretty much the SOS that Hitler and Stalin advocated...the outcome being, the end of liberty.
how does a free society, put the degenerate genie back in the bottle without a major, possibly armed, conflict
I think the answer may turn out to be: "It doesn't".
The fundamental problem is that "good government" simply does not exist. Nor do "good people". All forms of government are bad ... they have either to much power or not enough, and no truly effective way of policing themselves. All government suffers from the same problem: both the governors and the governed are corrupt sinners.