The primaries and general elections coincided with those for other federal offices, as well as those for state offices.
Turnout
Turnout in the state-run primary elections was 16.43% with a total of 836,458 votes cast. Turnout during the general election was 86.51%, with 4,757,409 votes cast.
Primaries
Non-binding state-run primaries were held on April 12.
Democratic
The 1960 Illinois Democratic presidential primary was held on April 12, 1960 in the U.S. state of Illinois as one of the Democratic Party's state primaries ahead of the 1960 presidential election. The popular vote was a non-binding "beauty contest". Delegates were instead elected by direct votes by congressional district on delegate candidates. All candidates were write-ins. Kennedy ran a write-in campaign, and no candidate actively ran against him in Illinois. Not all of the vote-getters had been declared candidates. Johnson, Stevenson, and Symington had all sat out the primaries. Chicago mayor Richard J. Daley, head of the Cook County Democratic Party, promised to deliver Kennedy the support of Cook County's delegates, so long as Kennedy won competitive primaries in other states.
Republican
The 1960 Illinois Republican presidential primary was held on April 12, 1960 in the U.S. state of Illinois as one of the Republican Party's state primaries ahead of the 1960 presidential election. The preference vote was a "beauty contest". Delegates were instead selected by direct-vote in each congressional districts on delegate candidates. Nixon ran unopposed in the primary.
Controversy
Some, including Republican legislators and journalists, believed that Kennedy benefited from vote fraud from Mayor Richard Daley's powerful Chicago political machine. Republicans tried and failed to overturn the results at the time—as well as in ten other states. Some journalists also later claimed that mobster Sam Giancana and his Chicago crime syndicate "played a role" in Kennedy's victory. Nixon's campaign staff urged him to pursue recounts and challenge the validity of Kennedy's victory, however, Nixon gave a speech three days after the election stating that he would not contest the election. A myth arose that Chicago Mayor Richard J. Daley held back much of the city's vote until the late morning hours of November 9. Yet when the Republican Chicago Tribune went to press, 79% of Cook County precincts had reported, compared with just 62% of Illinois's precincts overall. Moreover, Nixon never led in Illinois, and Kennedy's lead merely shrank as election night went on. Earl Mazo, a reporter for the pro-Nixon New York Herald Tribune and his biographer, investigated the voting in Chicago and "claimed to have discovered sufficient evidence of vote fraud to prove that the state was stolen for Kennedy." However, a special prosecutor assigned to the case brought charges against 650 people, which did not result in convictions. Three Chicago election workers were convicted of voter fraud in 1962 and served short terms in jail. Mazo, the Herald-Tribune reporter, later said that he "found names of the dead who had voted in Chicago, along with 56 people from one house." He found cases of Republican voter fraud in southern Illinois, but said that the totals "did not match the Chicago fraud he found."
