Administrative civil authority sends troops and pulls them.
Period.
If the AL governor did not know, which perhaps he would not, it was not the state of AL.
It had to be federal.
Dry run. Precedent.
Opinion:
Small town urban combat drill seeing if troops would obey/shoot and what the people of the small town would do.
What was the purported threat, requiring such an incursion? A single nutcase with a gun, who was killed, was supposed to wreak complete havoc on social order afterward, in a small, southern town?