Yeah, they are.
I was driving eastbound I-10 east of El Paso a few days ago. Lo and behold there was a permanent Border Patrol check point set up that we had to traverse. We were stopped, asked if we were American citizens, then flagged through. Others were pulled out of line and searched, and dogs were used. I’m wondering why it is acceptable for the US govt to set up interior police road blocks and stop american citizens travelling on private lawful business, but they can’t close the border?
Transportation choke point. Lot's of cars, busses, trucks, etc. go through there.
Strategery, don't ya know...
I’ve traveled that route many times. In my own car and a few times on a bus. I remember on one bus trip, a man came aboard at a stop who made fast friends with a woman and her baby. At the east-bound checkpoint, he was pulled off because he didn’t have documentation. He certainly made every effort till then to appear that he was “with” the woman.