Eugene McCarthy was a candidate in the 1968 Democratic presidential primary who drew a lot of youth support by challenging an “inevitable” establishment candidate from a boldly left position.

The election of a relatively young and tbh naive Democratic “culture hero” candidate 8 years earlier had raised hopes and even though the party had racked up some significant accomplishments since then, expanding the welfare state and drawing energy from a grassroots civil rights movement, this had more radicalized than satisfied the young activist base and they were looking for a candidate offering a more full-throated leftism, particularly in rejecting war and entanglement with the business establishment.

When it became clear that party insiders were actively trying, with ultimate success, to nominate anyone else for (ultimately futile) reasons of “electability” and interest-group logrolling clientelism, this caused significant disillusionment and further radicalization.