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

We have to remember that information sharing is restricted by legal barriers and cultural barriers and by the notion that information is power and therefore should be hoarded so if you share information you can extract something in exchange. In today's digital online world, those who don't share information will be isolated and left behind. We need the data of other countries to connect the dots.

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.

People in our so-called Rust Belt have lost out, and politics and society have not been responsive either in providing the kind of additional support they need or to retrain them for jobs that are being created in the new economy.

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

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.

There have been enormous advances since 9/11 to build a very robust set of targeting procedures and watch lists to screen travelers coming to the United States. The National Targeting Center in Virginia run by Customs and Border Protection checks the background of every traveler who seeks to enter the country.