@inthehandsPaul Cantrell I'm going suggest reading the first half of "Learning to Eat Soup with a Knife" by Col. John Nagl. https://www.amazon.com/Learning-Eat-Soup-Knife-Counterinsurgency/dp/0226567702 You're essentially fighting an insurgency of well-equipped fanatics who lack local support, logistics, and discipline. Nagl is smart, he revised the Army's counterinsurgency manual, and he compares how the British in Malaysia effectively defeated communist insurgents while still keeping the public on their side.

The book is not so much on military operation but on winning hearts and minds, showing how one army did and another army didn't in very similar conflicts.

That's essentially your challenge - direct armed confrontation will not work, surrender will not work, but the current tactics seem to slowly be working. Tracking them, getting in their way, goading them til they lose discipline, not letting them have a good night's rest, pressuring companies not to do business with them - all that corrodes their morale. The danger is someone else will snap and shoot another poet in the face again. But they've already proven they'll do that casually so there's really no additional risk.

They're an occupying force. Make them feel that every day until they leave. Make every Minnesota winter day that much colder and more miserable for them. Be like the northern Midwest winter and make them hate life.