In large part this is because of the success of policies followed by the United States to create an environment, a peaceful period in history in which economies could grow and countries could benefit.
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.
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 should be wary, particularly with our closest friends and allies, of breaking down the trust and confidence that lie at the foundation of relationships.
You need a strategy that involves layered defense: deployed patrols, sophisticated sensor equipment, and surveillance from the air. That is what has had a positive impact over the last generation.
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