In one of the first films of the direct cinema and probably the most famous one, Senator John F. Kennedy running for the Presidential nomination of the Democratic Party against Senator Hubert H. Humphrey in the Wisconsin Presidential Primary.
Text from Robert Drew

After 15 years as a LIFE magazine correspondent and editor, Robert Drew undertakes to translate LIFE’s candid still picture story telling into sound and motion pictures. He hopes to add power to the documentary film, which has been made static by heavy cameras and dull by heavy narration.
For five years Drew and his associates work to develop filming equipment light enough to be able to move freely with characters through a story as it happens. In nineteen sixty the new equipment is ready. For his first candid film Drew chooses the story of John F. Kennedy and his wife Jackie, campaigning for the Presidency in the Wisconsin primary election.
The freewheeling photography captures the characters, the flavor of campaign politics with an intimacy unmatched even today. PRIMARY is recognized as a breakthrough in film making. It is the first of four Drew films on the life and death of John F. Kennedy, the first of some sixty Drew candid films and the launch of American cinéma-vérité.