From what I understand, every non-official militia has one or two FBI agents in it’s membership.
BUT, most States have some sort of official militia. They train in such things as Emergency Management, First Aid, Disaster Relief etc. They also do have ranks and some do weapons practice/training. They do background checks on their members and don’t allow people with a criminal record in.
Just do a web search for militia + your state
“BUT, most States have some sort of official militia.”
These “militias” are formerly known as state guards. Twenty-six states have state guards. They are not associated with a state national guard. State guards are controlled by the state’s governor and cannot be drafted into duty by the federal government.
Here you go. This somewhat explains state guards but doesn’t get into the nitty-gritty of the power of state guards...
https://en.wikipedia.org/wiki/State_defense_force