On a hundred-year time scale you have more to fear from an unaccountable government than you do from radical Islam. A bureaucracy empowered to place you on a list where your rights can be excised or suspended will follow the inevitable path of all government agencies and programs: its scope will grow, it will become more opaque and resistant to oversight, and it will resist reform at every moment. Islamic terrorists have signifiers, tells, and structures we can attack with either our intelligence services or military options. Government agencies are nearly impervious to all forms of challenge.
The list that denies a potential terrorist the right to buy a gun today may expand to animal rights activists or Black Lives Matter protestors or anti-abortion campaigners tomorrow, all depending on the whim of the executive or even some a nameless bureaucrat. A list that stops you from boarding a plane today is a list that might deny you a license to drive, speak, or vote tomorrow.
The failure in Orlando wasn’t about guns; it was about law enforcement lacking the motivation and the tools to keep an eye on people sending every red-alert signal in the book. It was about failing to persistently target and track bad actors. It was about the FBI lacking either the will or the resources to monitor and follow Omar Mateen, despite feeling so strongly about him that they attempted to entrap him in the kind of terrorist act he later committed. He was an extremist well before he became a terrorist.