TUCSON, Ariz–Finishing my visit to the border back at Nogales, Ariz., the busiest port of entry in the state, it is easy to see the biggest future enemy to border security—growth.

The biggest problem in Nogales is that the cities on both side and cross-border trade exploded at the same time. The border crossing site is in the center of the town, hemmed in by the city on all sides with no room to expand.

All the attention on border security has ignored one of the most important requirements for keeping legitimate people, goods, and services moving across the border as quickly and efficiently as possible while thwarting the movement of bad goods and bad people: the infrastructure the roads, bridges, rail lines and ports America needs to keep America’s border the economic engine that helps fuel the American economy.

This is a challenge both the public and private sector need to spend a lot more time looking for solutions that enhance both American security and prosperity.