“Neither national nor international law appears likely to stop the U.S. government’s concerted efforts to deny due process to those placed on the No-Fly List. While today’s mechanisms of travel control are far more sophisticated than those that Mrs. Shipley had at her disposal, the net effect is virtually identical: Both U.S. citizens and those wishing to visit the United States are denied a fundamental human right. Hopefully, you’ll never be placed on the No Fly List. But if you are, you’ll appreciate the utility of a second passport, ‘just in case.’”
http://www.nestmann.com/passport-denials-long-a-feature-of-u-s-foreign-policy/