It does not have to be a government.
You want it to be.
I do not.
I do not agree with the premise that a temporary mutual aid agreement requires permanent authoritarian structures ruling over a particular place or group of people.
Discussion
A militia, with no predefined hierarchy, without regular and required training, that people join or ignore, depending on what they had for lunch, is just a messy mob.
no, it's not. a local militia knows their own territory they must defend better than anyone, that's the whole point.
I know groups that are not a messy mob and entirely voluntary . . . So . . . I respectfully submit that you are wrong.
Also, people in a militia can have a perfectly functioning hierarchy without there being any coercion. Again, I see it. And, in some ways, it is a growing thing.
Heck, that's how the early church was with the ecclesia. (Granted, there were leaders that were appointed through apostolic succession, but I am explicitly not conflating those with any human governance, as that is a separate thing. IMO.)
And yet they wiped the floor with SEALs in Operation Red Wings. SEALs didn't even get a shot off.
You underestimate the capabilities of non-state militias, ma'am.
The trick is getting them to train often-enough and remain up to date in the absence of a clear and present danger. No, I don't have an easy solution.