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.

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

We need to realize that the economic situation between Mexico and the United States is not just one in which we trade with one another. We make things together. We have shared production platforms. Cross-border trade is part of a single production process, and while apparently the Trump administration will seek to re-examine elements of that production platform, it is what it is and won't be easily dismantled.

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.

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.

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.

The image and the costs of a Berlin-like wall or a Great Wall of China is something that the American people have not accepted to date.