Then put the detainees behind barbed wire in desert POW compounds because that's precisely what they are - POWs! They are part and parcel of the enemy's ground troops in an undeclared war against the United States. Oh, and if the Guard spots any armed coyotes or drug cartel members, have them shoot to kill.
As a bonus, you'll be the next President of the United States!
Believe me, this nonsense will stop, el quicko!
The feds could stop the tide of illegal immigration any time they want. The could have done it decades ago. That the problem still exists means they want it that way. Anything else you hear from them, anything they say, is just smoke screen diverting your attention from that fact.