The seven banned countries
The two countries in which ISIS is geographically located. ISIS is an abbreviation for Islamic State of Iraq and Syria.
An enemy of the United States, one of George W. Bush’s three “axis of evil” countries.
Lawless countries (in other words there is no central government in control) that are prime recruiting grounds for jihadists.
People have asked why certain other countries aren’t banned. It’s because they don’t fall into one of those three categories. For example, although Saudi Arabia is a Muslim country, it’s not lawless, not an enemy of the United States, and not the location of ISIS.