One thing that has become a tiresome part of major American conventions and gatherings that have some expected controversial dimension is the extent to which many municipal, county or state governments subcontract out some portion of their police force to acts of intimidation and prior restraint against possible protest, acts that they know are not going to hold up to later court challenges. It’s not much different than what authoritarian states do when there’s a big event in town except for that last part, the costs paid out later on when courts say, “Um, that wasn’t allowed.”
Cities that want major sports franchises now know that they’re almost certainly going to have to pony up a big portion of the funding and defer most or all of the direct tax revenue from the stadium, leaving mayors and city councils making fumbling, weak arguments about indirect economic benefits, “world-class status” and so on. Only rarely do municipal leaders have the guts to say no when a big team threatens to leave town.
I think it’s roughly the same case here. You make a pitch to have the RNC or DNC come to town, or for the WTO to meet in your city, or anything with a similar possibility to attract protest. Not only do you budget for additional security, you budget the cost of the legal judgments you’re almost certain to lose from permitting law enforcement to illegally confiscate property, harass protesters, bend the terms of warrants or ignore them altogether, and carrying out false arrests. It’s lose-lose for a city to host under these terms: you lose prestige because you let some group of your own goons (or maybe some federal goons that you allowed in) screw around with legitimate protest and you lose money to boot.
This is also a good example of why it’s a mistake to call upon federal or state power to enforce restrictions on your political opponents. “Free speech zones”, the use of RICO to inflict damage on abortion opponents and so on are just as readily useful devices against other kinds of protest. There’s no way to confine some kinds of enforcement strategies and tactics just to the people you oppose. Once you give the guys with badges some new kind of hammer, I guarantee they’ll find some new nails. About the only answer once that starts happening is to inflict enormous political and fiscal penalties on enforcement agencies and governmental bodies that start using their new tools enthusiastically.