The nation's top military official has apologized for taking part in President Donald Trump's walk from the White House to St. John's Church for what eventually turned into a controversial photo op after authorities had used pepper balls and smoke canisters to disperse largely peaceful protesters. "I should not have been there," said Gen. Mark Milley, the chairman of the Joint Chiefs of Staff, in a prerecorded video commencement address to National Defense University. "My presence in that moment and in that environment created a perception of the military involved in domestic politics."