The State Department said Thursday that Republican subpoenas to interview witnesses to the Benghazi terror attack could “jeopardize” the FBI's investigation. House Oversight Committee Chairman Darrell Issa (R-Calif.) announced Thursday that he has subpoenaed John Martinec, the top security adviser to slain U.S. Ambassador to Libya Christopher Stevens, who was killed in the attack. Issa has also subpoenaed Alec Henderson, the regional security officer in Benghazi. “We understand that the Diplomatic Security law enforcement agents who performed heroically on September 11 are likely witnesses at any criminal proceedings relating to the Benghazi attacks, and that additional interviews of them outside...