1980 October Surprise theory
en.wikipedia.org

... The 1980 October Surprise theory refers to an allegation that representatives of Ronald Reagan's presidential campaign made a secret deal with Iranian leaders to delay the release of American hostages until after the election between Reagan and President Jimmy Carter, the incumbent.[1]

The detention of 66 Americans in Iran, held hostage since November 4, 1979, was one of the leading national issues during 1980,[2] and the alleged goal of the deal was to thwart Carter from pulling off an "October surprise".[3][4] Reagan won the election, and, on the day of his inauguration"minutes after he concluded his 20-minute inaugural address"the Islamic Republic of Iran announced the release of the hostages.[5] ...

A Short History of Everyone Who Confirmed Reagan's October Surprise Before the New York Times (March 2023)
theintercept.com

... On Saturday, the New York Times published a blockbuster story that said two prominent Texas Republicans flew across the Mideast in the summer of 1980 for secret meetings with regional leaders to urge them to tell Iran to keep the U.S. hostages in Tehran until after the election that pitted GOP candidate Ronald Reagan against then-President Jimmy Carter.

The Times reported that Ben Barnes, a key figure in Texas politics, said he made the trip with former Texas Gov. John Connally, a major supporter of Reagan's campaign, and that when they returned home, Connally met in an airport lounge with William Casey, who'd been a top U.S. spy during World War II and was then Reagan's campaign manager. Connally and Casey discussed the trip, according to Barnes, who The Times quoted as saying, "History needs to know that this happened." After Reagan beat Carter in a landslide, Reagan appointed Casey head of the Central Intelligence Agency.

All this is powerful evidence that the Reagan campaign did -- as has been alleged for decades -- strike a deal with the Iranian government to prevent the hostages from being released. While that has never been proven, what's known beyond a shadow of a doubt is that the Reagan campaign was deeply worried that Carter might get the hostages out before November and thereby give a big boost to his prospects.

You might understandably ask: If this actually happened, how could it have been kept secret? Why hasn't anyone with knowledge of it spoken up before? The answer is that it hasn't been kept secret, and many, many people have said it occurred. But most of the people doing so have been foreigners. Barnes is merely the most important American to finally come out and support the story. ...