EXCLUSIVE: One of the classified email chains discovered on Hillary Clinton's personal unsecured server discussed an Afghan national's ties to the CIA and a report that he was on the agency's payroll, a U.S. government official with knowledge of the document told Fox News. The discussion of a foreign national working with the U.S. government raises security implications – an executive order signed by President Obama said such unauthorized disclosures are 'presumed to cause damage to the national security." The U.S. government official said the Clinton email exchange, which referred to a New York Times report, was among 29 classified...