I believe that technically the Indian reservations are sovereigh nations with their own laws, so if the Indian police arrested these Customs agents and tried them for trespassing, it might put a stop to this stuff. Of course, if I were a sovereign nation of a couple of hundred square miles surrounded by the world's greatest ever super-power, I might think twice about that course of action.
> I believe that technically the Indian reservations are sovereigh nations ...
They are. Which means... the US *could* set up borders around them... gotta have your passport ready to go in and out, say. There is, I believe, nothing wrong with this; it would be an effective card to play if a particular sovereign rez started getting out of hand. If you drove all the way to the rez for a gallon of milk, a pack of smokes or a game of blackjack and you didn't have your passport, you don't get in, and the rez doesn't get your money.
This sort of tactic should be used sparingly but strategically. Whether a state governemnt could set up roadbloack, border crossings and checkpoints, I kinda doubt... but it might be interestign to look into.
.....I might think twice about that course of action.....
I would heartily recommend reading some ( actually all) of the Tony Hillerman books that have the subject of the interaction of the Tribal Nations with the American Nation at the tribal level. The books are not only great cop mysteries, they delve deply into the Navajo mind. They are also great travelogues if you plan to visit the Four Corners region.
It turns out that the FBI is the chief law enforcement agency, having jurisdictional authority for many crimes.
Hillerman's protagonists Officer Jim Chee and Lt Leaphorn, officers with the Navajo Tribal police, are frequently frustrated by the failure of the FBI to adequately do their job. The reverse is also true as they work together to solve crimes in the Big Rez.