President Johnson quickly issued an executive order to create the Warren Commission—chaired by Chief Justice Earl Warren—to investigate the assassination. The commission concluded that Oswald acted alone in killing Kennedy and that Oswald was not part of any conspiracy.[365] The results of this investigation are disputed by many.[366] The assassination proved to be a pivotal moment in U.S. history because of its impact on the nation, and the ensuing political repercussions. A 2004 Fox News poll found that 66% of Americans thought there had been a conspiracy to kill President Kennedy, while 74% thought that there had been a cover-up.[367] A Gallup Poll in November 2013 showed 61% believed in a conspiracy, and only 30% thought that Oswald did it alone.[368] In 1979, the U.S. House Select Committee on Assassinations concluded, with one third of the committee dissenting, that it believed "that Kennedy was probably assassinated as a result of a conspiracy. The committee was unable to identify the other gunmen or the extent of the conspiracy."This conclusion was based largely on audio recordings of the shooting.