"Sick later published a book (October Surprise: America's Hostages in Iran and the Election of Ronald Reagan),^[10] published in November 1991, on the subject. Sick's credibility was boosted by the fact that he was a retired naval captain, served on Ford's, Carter's, and Reagan's National Security Council, and held high positions with many prominent organizations; moreover, he had authored a book recently on US-Iran relations (All Fall Down). Sick wrote that in October 1980, officials in Ronald Reagan's presidential campaign, including future CIA Director William Casey, made a secret deal with Iran to delay the release of the American hostages until after the election; in return for this, the United States purportedly arranged for Israel to ship weapons to Iran.

Sick admitted that "The story is tangled and murky, and it may never be fully unraveled." He was unable to prove his claims, including that, in the days before the presidential election with daily press pools surrounding him and a public travel schedule, vice presidential candidate George H. W. Bush secretly left the country and met with Iranian officials in France to discuss the fate of the hostages.^[37]"

https://en.wikipedia.org/wiki/1980_October_Surprise_theory#:~:text=Sick%20wrote%20that%20in%20October,Israel%20to%20ship%20weapons%20to