per Trump's Department of Homeland Security. The report states restricting immigration solely by citizenship unlikely to predict terror attacks; the largest source of terror attacks in the US are American citizens not foreign immigrants; most countries that have sent terror attackers are not in Trump's travel ban at all; most of the countries in Trump's travel ban have never sent a deadly terror attacker to the US; most countries on Trump's travel ban are dangerous to visit and pose threats to neighboring countries but are not a threat to send an attacker to the US like Saudi Arabia did in 911. And of course Saudi Arabia is not on the list.