Lowenstein was critical of the official account of the June 6, 1968, assassination of Senator Robert F. Kennedy. Lowenstein made a one-hour appearance on the PBS television show Firing Line in 1975, where he was interviewed by William F. Buckley Jr., in which he stated that he did not believe that Sirhan Sirhan alone had shot Kennedy, Schrade and the four others who were injured in the shooting are often overlooked players in the assassination that killed Kennedy at the age of 42 amid his ascendant presidential campaign.

When Schrade gained consciousness at a nearby hospital, a United Automobile Workers leader came to his bedside and told him the news: Kennedy was dead.