Following a failed attempt by Umar Farouk Abdulmutallab to blow up a flight into Detroit on Christmas morning, the Transportation Security Administration imposed tougher screening rules for passengers originating in 14 mostly Muslim nations. See more about the countries selected.

Geoff Porter, the head of Middle Eastern and African affairs for the Eurasia Group, examines the extent to which the business relationship between the U.K. and Libya influenced the decision to release the Lockerbie bomber.