People should remember that Mexican migration is now at a net negative. More Mexicans are leaving through deportation and voluntary return than are entering the United States legally and illegally.

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.

Walls and barriers alone are insufficient to insure security.

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

I think there's no question that the barriers, the fences and in certain urban areas, the walls, have had an important effect in terms of increasing the manageability and the security of the border. But in fact as Secretary of Homeland Security General John Kelly acknowledged at his confirmation hearing, walls and barriers alone are insufficient to insure security.

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.

Indeed, many of the illegal crossers who have entered the country in the last two years after being detained have actually been either unaccompanied minors or families who request political asylum. The ability of the smugglers to attract large numbers of families and unaccompanied minors is a function of the inability of our immigration court system to process asylum claims in a timely fashion.