Piles of trash and miles of fencing will greet President Joe Biden when he arrives in Brownsville, Texas, on Thursday for the second border visit of his presidency. What will be missing are illegal migrants crossing the border. At Camp Monument, once a bustling center run by U.S. Custom and Border Patrol to process migrants who illegally entered the country in Brownsville, there were few signs of activity on Wednesday. Rows of fencing, entwined with concertina wire, shone in the hot Texas sun. The 12-foot-tall wire fence panels are laced with a 3-foot looping layer of concertina wire in order...