Kennedy's election in 1960 over Nixon involved heavy fraud in Illinois and Texas. (If Nixon had won those two states, he would have won the presidency.)
As examples of ballot box stuffing: In Texas's Angelina County, in one precinct, only 86 people voted yet the final tally was 147 for Kennedy, 24 for Nixon; in Fannin County the 4895 registered voters cast 6138 votes (75% for Kennedy). Discarded spoiled ballots were to be placed by Texas law in "ballot box 4" for later re-examination, but many counties (e.g. Fort Bend County, which had a huge 16% spoilage rate, topping even the worst Florida 2000 County) just discarded them, and did not store them, making any biased discarding decisions uncorrectable and unprovable. The 100%-Democrat Texas Election Board refused to conduct a recount
, so game over.
Kennedy carried Illinois by 8858 votes thanks to a 456,312-vote advantage in Chicago, whose precincts reported their totals remarkably late. (Compare this with Kennedy's nationwide victory margin of 118,574.)
The "turnout" in Daley-machine Chicago was a spectacular 89%. This contrasts with the nationwide turnout of 63%. It also contrasts with the fact that in the 11 presidential elections during 1960-2000, totalling 550 statewide contests, not once did any state ever exceed 1964 Utah's 78.4% turnout, and the states with the largest-% turnout were always rural (namely North and South Dakota, Utah, Minnesota, and Maine), not urban.
In 1992 mob boss Sam Giancana's nephew and brother wrote a book ["Double Cross: The Explosive, Inside Story of the Mobster Who Controlled America," Warner books] again recounting how Giancana had rigged the Cook County vote for Kennedy as part of a deal, and further stating that when Kennedy reneged on the deal, Giancana had him assassinated. (They claimed they had heard this directly from Giancana himself who also noted "Richard Nixon and Lyndon Johnson knew about the whole damn thing." The book also linked Giancana to a total of 7 US Presidents.) Giancana and Kennedy both shared Judith Campbell Exner as mistress.
Circuit Court Judge Thomas Kluczynski, a Daley machine loyalist, dismissed Republican lawsuits, for which Kennedy rewarded him by appointment to the federal bench. Recounts were generally blocked by Daley cronies, but special prosecutor (a Democrat!) Morris Wexler found that the simultaneous IL Attorney General race had been massively corrupted to defeat Adamowski (8875 extra Adamowski votes were found during a partial recount, i.e. exceeding the Kennedy-Nixon margin) and embarked on 667 prosecutions, but the Daley machine trumped that by getting a judge to dismiss all the charges en masse, and game over. During the 1960 election, 176 out of 180 positions on the Board of Election Commissioners were Daley Democrats. In 1962, after an election judge confessed to witnessing vote tampering in Chicago's 28th ward, three precinct workers pled guilty and served short jail terms. Reporter Earl Mazo, visiting the Chicago address where 56 Kennedy voters "lived," found an abandoned demolished house. He also found a cemetary where all the tombstone names were registered voters. In Ward 27, Precinct 27, the 376 voters cast 397 votes; In the 15th precinct of ward 2, Kennedy beat Nixon 74-to-3 but only 22 people were registered to vote.
Following Kennedy's election, he appointed his brother Bobby (who would seem to be somewhat underqualified, e.g. he'd never argued a case in a courtroom) US attorney general, and Bobby shut down all federal investigations into voting fraud.
Some cleanup of the Daley machine finally occurred in the early 1970s after the Chicago Tribune hatched a plan in 1972 to get 20 of its reporters to become precinct officials so they could see the machine from inside; this plan resulted in 40 indictments for election fraud. They observed countless cases of workers illegally helping voters and distributing partisan literature. Vote-buying including "chain voting" was done openly. Election observers were threatened with death. Others were simply refused permission to observe. The livelihood of the "precinct captains" was based on the votes they "delivered." They had quotas that differed in different precincts based on past history, and had to deliver quota or lose job. Counts were falsified. Democrat party bosses controlled all the election judge appointments. 82% of Republican election judges admitted they had been recruited and appointed by Democratic ward bosses.