https://en.wikipedia.org/wiki/1948_United_States_Senate_elec...
>The validity of the runoff election was challenged before the US Supreme Court due to allegations of election fraud, and in later years, testimony by parties involved indicated that widespread fraud occurred and that friendly political machines[3] produced the fraudulent votes needed for Johnson to have a numerical majority, in effect stealing the election.
https://en.wikipedia.org/wiki/1960_United_States_presidentia...
> Some, including Republican legislators and journalists, believed that Kennedy benefited from vote fraud from Mayor Richard Daley's powerful Chicago political machine. [12] Mayor Daley’s machine was known for "delivering whopping Democratic tallies by fair means and foul."[13] Republicans tried and failed to overturn the results at the time—as well as in ten other states.[13] Some journalists also later claimed that mobster Sam Giancana and his Chicago crime syndicate "played a role" in Kennedy's victory. [13] 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.[14]