The term “October Surprise” originated against the backdrop of President Jimmy Carter’s 1980 reelection campaign. The Iranian hostage crisis overshadowed the last year of Carter’s presidency. William Casey, Ronald Reagan’s campaign manager, coined the term to describe the possibility that a last-minute hostage release might give his campaign a shot of adrenaline to enable him to win a second term. It took a conspiratorial turn when Gary Sick, a Carter national security aide, suggested that Reagan’s team had conspired with Iranian revolutionaries to delay the hostage release. The theory was later disproved.

Still, campaigns obsess about a last-minute surprise.