An Apple employee instructs a journalist on the use of the fingerprint scanner technology built into the company's iPhone 5S during a media event in Beijing. Watchdog groups are concerned that U.S. Customs and Border Protection agents are searching the phones and other digital devices of international travelers at border checkpoints in U.S. airports. (AP/Ng Han Guan)

Groups Decry Trump Plan to Demand Social Media Passwords At US Border

DHS Secretary John Kelly has defended the idea, saying that if travelers “don’t cooperate…they can go back.”