The government should take either the state of Wyoming (or Montana, some empty state no one cares about) and build a 20ft wall around the entire border. Inside the new enclosure, there are absolutely no rules. None. Absolutely none. The only law is the law of the jungle.
There will be an entry/exit checkpoint at the border and citizens can come and go as they like (all existing laws of course are strictly enforced outside the anarchy zone and there will be a customs checkpoint to ensure no illegal items are taken out of the zone). Entrance and exit to the zone is completely voluntary and trade from the zone to the rest of the nation is allowed (as long as it's legal, exports of guns and drugs would be refused, for example). Any "crimes" committed in the zone will not be investigated by law enforcement and no lawsuits about activities in the zone will be heard in court.
It would be an interesting experiment, what would happen in the zone?