Migration to the U.S.-Mexico border, once overwhelmingly a Mexican phenomenon, has diversified and become increasingly hemispheric in nature. As the immigration flows become more complex and the encounters of arriving asylum seekers and other migrants surge to record levels, how are U.S. border operations and policies evolving? And what is driving rising immigration from across Latin America, the Caribbean, and beyond? Migration Policy Institute President Andrew Selee speaks with two colleagues who traveled from one end of the nearly 2,000-mile boundary to the other, touring U.S. Customs and Border Protection facilities and interviewing U.S. and Mexican officials, NGO leaders, and others.