Thanks for this measured reply.
My first response is: Our relationship to refugees is SO different than that of European countries that, again, this doesn't seem to be more than a fear tactic. In 2016, Germany took 1,000,000 Syrian refugees. We took 10,000. All of this while we have a population that is 4x Germany's. If anything, we already look protectionist & selfish on the world stage -- we have the refugee equivalent of a mile-high, neon Beware of Dog sign with a shrieking siren. We don't need to further emphasize that stance for optics. I do not know a single person who works in immigration or refugee vetting (and I live in DC and have friends who are actively involved on a daily basis from big picture policy at DHS to being refugee interviewers at ICE to foreign service consular officers) who thinks our system is thin or loose.
My second response is: There are perception consequences in both directions, and the insistent and heightened drama of 'extreme vetting' (and especially Trump's chosen language around it) also makes us seem biased in the global context. This is highlighted by the Ayatollah's recent remarks that we're showing our true face. This kind of posturing feeds into the motivating rhetoric of extremists. To me that's a much, much more significant danger.
Finally: I'm not flippant about the reality that there are serious threats in the world. Clearly there were threats we didn't perceive prior to 9/11. But the answers aren't simplistic & obvious, which is why we need to focus on empowering intelligence professionals who are focused on identifying unknown/new/innovative tactics. We're well-practiced at responding to known threats -- our relative safety for the past 15 years seems to be the best indicator of this. We aren't going to be made safer by appealing to raw fear & belligerence.