The problem I see with a bunch of people's forming a militia group to do X Y or Z is the same problem that I see happening in the Middle Eastern countries westerners and USA invades. Those rag tag militia groups are still fighting to this day. I would argue just from a practical perspective that enough people do not want the western countries/USA expelled from their country strong enough to where they will do much of anything about it.

Are the gangs of Muslim Brotherhood and smaller groups not militias? I don't see them as winning against a centrally planned power anytime soon. If China was dealing with the Middle East they would probably just slaughter more people to get them in line, whereas the Western countries slaughter people but not in a high enough magnitude to end anything. Slaughtering people is bad that should go without saying, just pointing out that these gangs/militias don't seem to be capable of repelling modern forces.

How can a militia defend against drones/air superiority for example. It is really hard to do something against that for any individual or small group. The founding fathers defintely did not have the forethought to see a future in which the skies are dominated or robots control things via AI(similar to the Terminator movies).

If US citizens could throw off the shackles of government, agree to disband everything and start over with voluntary agreements where people join and pay "taxes" at their own free will, and everything is voluntary and we have a drone army/army/airplanes/carriers/ships/submarines/etc and that works out I would support it. I just don't see that happening in my life time to be honest. It will require a radical shift in the way humans think to accomplish such things.