Ex-Secret Service agent: Expect ‘unprecedented level’ of officers during Trump’s Michigan rally MLive.comSecret Service spotted Trump rally shooter on roof 20 minutes before gunfire erupted ABC NewsVideo: How Trump’s Security Failed to Stop an Assassination Attempt The New York TimesExclusive video appears to show would-be Trump assassin at rally before shooting CNNOpinion | Incivility and the Tragedy of the Commons The Wall Street Journal