If these guys are there, snatching people off the streets without legal justification, their city is obligated to protect them. If the goons doing the kidnapping are armed and have no city or state mandate for their actions, they should expect the localities in which they intend to perform their illegal actions to defend themselves with whatever means they have at their disposal.
If this is the civil war that Putin has long hoped to provoke, he has set up his (Trump's/Barr's) side very skillfully. Smaller towns and sparsely populated states may not have the means to enforce adherence to the Bill of Rights by federal intruders of questionable legality. Philadelphia and Pennsylvania do. An oral "William Barr sent me" will not suffice as a get-out-of-jail-free card. The response should be, "James Madison sent me. Hands behind your back, and don't move. You have the right to remain silent, and unless you want to piss me off, you should make use of it."