When the Chair of the Joint Chiefs of Staff Gen. Mark Milley enters into his scheduled retirement later this year, one of the perks will include a personal security detail to protect him from threats — including “embarrassment.” The U.S. Army Protective Services Battalion, the Pentagon’s little-known Secret Service equivalent, is tasked with safeguarding top military brass. The unit protects current as well as former high-ranking military officers from “assassination, kidnapping, injury or embarrassment,” according to Army records. Protective Services’s mandate has expanded to include monitoring social media for “direct, indirect, and veiled” threats and identifying “negative sentiment” regarding its…