If shay's rebellion happened after the constitution, the local militia will probably be taking a hand in it, and try to peacefully stop riot with the farmers and commoners. If not then they will raise there guns and use fear to scare them away and maybe take some prisoners or some shots. If it gets very bad, then I propose that the president would create marshal law over the area. If people try to find ways to go around it, then article 8 of the constitution, says that the US has the authority to catch and punish the people accordingly if they do such felonies.