“The customs department of the Department of Homeland Security is going to have to grow with trade and legal tourism,” Rosenberg said. “We’ve got to invest more in border infrastructure. We’ve got to cut down on wait times.”Doing so would also help eliminate barriers to further trade between the two countries, said Shannon O’Neil, a senior policy fellow for Latin American studies at the Council on Foreign Relations. And further trade means growing economies on both sides of border, particularly in areas near the border.“When a Ford plant opens in Mexico, it increases employment in the U.S.,” O’Neil said. That is because manufacturing companies take advantage of the free-trade laws that allow easy passage between North American nations to produce different parts in different places for the same finished product.