Watergate prosecutors had evidence that operatives for then-President Richard Nixon planned an assault on anti-war demonstrators in 1972, including potentially physically attacking Vietnam whistleblower Daniel Ellsberg, according to a never-before-published memo obtained by NBC News. The document, an 18-page 1973 investigative memorandum from the Watergate Special Prosecution Force, sheds new light on how prosecutors were investigating attempts at domestic political violence by Nixon aides, an extremely serious charge. A plot to physically attack Ellsberg is notable because the former Pentagon official has long alleged that Nixon operatives did more than steal his medical files, the most well-known effort to discredit him. [The memo] states that an extensive investigation" found evidence that Nixon operatives plotted an "assault on antiwar demonstrators" at a rally at the U.S. Capitol featuring Ellsberg and other anti-war "notables." The anti-war demonstration occurred near a viewing of recently deceased FBI Director J. Edgar Hoover. An accompanying memo [states that] the attack would be on "long-haired demonstrators, in particular Ellsberg" ... with the objectives of impugning Ellsberg for protesting near to Hoover lying in state and "simply having Ellsberg beaten up."