Tijuana, Mexico, left, and San Diego, Calif, right, are seen separated by the U.S. border fence, on Saturday, Dec. 22, 2018. The Trump administration's decision to make asylum seekers wait in Mexico while their cases wind through clogged U.S. courts was announced with crucial details still unknown - a move that creates uncertainty along the border and possibly an incentive for people to cross illegally before the change take effect. (AP Photo/Daniel Ochoa de Olza)