In the last generation we've moved past a U.S.-Mexico relationship that while friendly on the surface, and demilitarized for the most part, really was not a genuinely cooperative relationship. As a result of the U.S.-Mexico War in the 19th century, and the treaty of Guadalupe Hidalgo in 1848, half of what was Mexico was severed and became much of the western part of the United States. To add insult to injury, most Americans never knew that, and most Mexicans have never forgotten it.

In today's digital online world, those who don't share information will be isolated and left behind.

Homeland security is inherently transnational today. There's hardly anything adverse that happens in our homeland that doesn't have a cause or effect that's generated abroad. Increasingly, we must rely on our allies and foreign governments to share information and data to secure our country.

We should be wary, particularly with our closest friends and allies, of breaking down the trust and confidence that lie at the foundation of relationships.

Not only are the numbers of migrants entering the United States at the lowest levels in a generation, but they are now largely Central American. Four out of five border-crossers detained in South Texas are Guatemalan, Honduran or Salvadoran. They are driven by violence and poverty in their home countries and the desire for family reunification.

The nationalism and the protectionism that was built into the Mexican Revolution in 1910 and that characterized the Mexican attitude to the United States for much of the 20th century were difficult to overcome. But that actually has occurred. And the cooperation, trust and confidence that have been built is not something that should be abandoned without great consideration for the potentially grave consequences to the United States.

Mexico has become a robust democracy with a robust press and an active legislature. It has gone from being a sending country for migrants to a transit country, and increasingly a receiving country for migrants in its own right.