When I first read the question, I thought "Heck yeah! Neo-nazis and white supremacist should totally lose their citizenship! Though I doubt the republican party will agree to this." Then I read the actual wording below and I am concerned. I mean, yes, by all means, if an American decides to join Hamas or Isis or what not, there should be consequences. However the training and material clause can be very problematic. The US trained and armed Al-Queda and much of the middle east. Are we going to take away the citizenship of former presidents and military and intelligence members? I think the overall concept is not bad, but as worded it sounds like there will be a lot of incorrect decisions made.