One of the biggest question marks hanging over Hillary Clinton's presidential campaign is the Justice Department's ongoing investigation of the private server Clinton used for email while secretary of state, specifically whether the arrangement compromised government secrets. The inquiry is focused on email exchanges between the U.S. ambassador in Pakistan and State Department officials over whether to oppose specific CIA drone strikes, The Wall Street Journal reports, citing "congressional and law-enforcement officials briefed on the Federal Bureau of Investigation probe."
During Clinton's tenure, the CIA was at loggerheads with officials at the State and Defense Departments over the high number of drone strikes in Pakistan, and under a compromise brokered in 2011, State Department officials were permitted to endorse or oppose specific strikes. The messages were usually sent via a secure government network, but on about six occasions, given tight time constraints, they were sent on the "low side," or on less-secure networks, The Journal reports. The vaguely worded emails — they didn't mention "drones," "CIA," or any details about targets — were sometimes forwarded to Clinton. The Journal elaborates:
The CIA drone campaign, though widely reported in Pakistan, is treated as secret by the U.S. government. Under strict U.S. classification rules, U.S. officials have been barred from discussing strikes publicly and even privately outside of secure communications systems. The State Department said in January that 22 emails on Mrs. Clinton's personal server at her home have been judged to contain top-secret information and aren't being publicly released. Many of them dealt with whether diplomats concurred or not with the CIA drone strikes, congressional and law-enforcement officials said. [The Wall Street Journal]
No criminal charges are likely, The Journal says, citing "several law enforcement officials," in part because officials at many departments (including Justice and Defense) "have occasionally resorted to the low-side system to give each other notice about sensitive but fast-moving events." But the FBI won't make any decision until it interviews Clinton this summer and reviews all the evidence. You can read more about the bureaucratic drone battle and how it relates to Clinton's emails at The Wall Street Journal.