A 72-year-old man was charged with threatening to assault and kill a federal judge in Minnesota, the Justice Departmentsaid Tuesday, after a summer marked by two high-profile shootings in the state and amid growing concern about threats against judges. Law enforcement responded Wednesday after Robert Phillip Ivers printed copies of a 236-page "manifesto" at a library in Wayzata- a Minneapolis suburb - titled "How to Kill a Federal Judge," according to prosecutors. The document allegedly described killing judges and children and names at least two federal judges.