however the others were in the US legally which means they would have been able to carry out their terrorist attack.
Trump is not right all the time. Sometimes he says stupid stuff.
Mohamed Atta was the ringleader. He should have been deported. Stop making excuses for Jeb.
Since the majority of them were NOT here legally, had they been flagged (in a nation where immigration law is actually taken seriously and enforced) it is very unlikely they would have succeeded in their quest. If I cut your attacking army in half, do you still possess the same odds of winning the engagement?