If Trump declares Minnesota to be in a state of insurrection the state and local governments are federalized (buh-bye DFL), martial law declared, the army hits the streets, strict curfew, and arrest all involved with the riots (including pubic officials).

Trials during martial law are not carried out by civil courts, they are military tribunals. That means none of the rioters are going to get a slap on the wrist and the entire Minnesota government (including some congresscritters) just might get a long Caribbean vacation at Guantanamo Bay.