If you build a 50-foot wall, you'll soon be confronted with a 51-foot ladder.

Mexico now has the 13th largest economy in the world. The Organization for Economic Cooperation and Development predicts it will have a larger economy than Germany by 2042.

Most people who live at the border or are familiar with the border know that a Berlin-like wall stretching from San Diego to Brownsville is not necessary. And the costs would be prohibitive. And there are places on the border, such as the Arizona desert or the open terrain around the Big Bend in South Texas, where Mother Nature has created her own barrier that is not easily passable. Or if you do pass through it, you are easily detected.

We can't defend the country by looking at the borderline as the first line of defense rather than as the last line of defense. We have to secure the flow of goods and people by engaging with foreign entities. We assure our security by securing the flows as early as we can before they arrive and as far away from our borders as we can.

Walls and barriers alone are insufficient to insure security.

The Mexican people are increasingly middle class, and Mexico has substantially become a middle-class society. This is true despite the significant poverty, and the class and geographic inequality that have deep historical roots.

Until we have a legitimate labor market between Mexico and the United States, people will attempt to come here to work.