Trump was advised to just copy Obama's order but he did not and wasted his time and effort on orders that everyone knew were going to have constitutional defects. Not only that, but Obama's approach of vetting people and what they did and where they went was better than looking at citizenship. The London Bomber was not from one of Trump's six countries. He was however from one of 7 countries Obama had on a vetting checklist regarding where people travelled and where terrorist training camps were located.