FILE - In this Dec. 10, 2018, file photo, people look on from the Mexican side, left, as U.S. Border Patrol agents on the other side of the U.S. border wall in San Diego prepare for the arrival of hundreds of pro-migration protestors, seen from Tijuana, Mexico. The southern border is nearly 2,000 miles long and already has about 650 miles of different types of barriers, including short vehicle barricades and tall, steel fences that go up to 30 feet high. (AP Photo/Rebecca Blackwell, File)