Anti-Vietnam War candidate Sen. Eugene McCarthy of Minnesota won Wisconsin's April 2 Democratic primary, following his second-place finish in New Hampshire the previous month. McCarthy's win in Wisconsin demonstrated the strength of the anti-war movement in the Democratic electorate, which, coupled with Robert Kennedy's decision to also enter the race, led to incumbent President Lyndon Johnson's decision not to seek another term. Johnson's vice president, Hubert Humphrey, ultimately won the Democratic nomination at the Democratic National Convention, and then lost the general election to Richard Nixon.

Wisconsin Democratic primary election resultsDate: April 2, 1968Winner: Eugene McCarthyVotes for: 412,160 (56%)Runner up: Lyndon Johnson (35%)Wisconsin general election resultsDate: Nov. 5, 1968Winner: Richard NixonVotes for: 809,997 (48%)National winner: Richard Nixon