Particularly remembered for his contributions to the Free Speech Movement of the mid-to-late 20th century, this political theory professor and scholar published several important works, including Loyalty in America (1957) and Escape from Authority: The Perspectives of Erich Fromm (1961).
After completing his bachelor's degree, master's degree, and doctorate at the University of California, Los Angeles, he began his teaching career at the University of California, Berkeley, and later joined the faculty of the University of California, Santa Cruz.
His high-profile students include political activist Frank Bardacke and political scientist Wilson Carey McWilliams.
A native of Montoursville, Pennsylvania, he grew up on a farm and was raised in the Lutheran faith. He was married to fellow political theory scholar Hanna Fenichel Pitkin.
He was a contemporary of economist and fellow political theorist Julian Simon.