An 'October surprise' could still spell trouble for Kamala Harris, Hillary Clinton warns

Kamala Harris and Donald Trump’s campaigns can’t get too comfortable in the final weeks leading up to the presidential election. An “October surprise” might be around the corner.

Trump’s 2016 opponent, Hillary Clinton, is all too familiar with how an October surprise – a major, unexpected news story about a candidate – can derail a campaign during its final stretch and ultimately influence the outcome of an election. Hers came less than a month before Election Day, when Wikileaks began releasing her emails.

She’s now warning Harris to expect an October surprise of her own.

“I anticipate something will happen in October, as it always does,” Clinton said in a recent interview with PBS. “…There will be concerted efforts to distort and pervert Kamala Harris, who she is, what she stands for, what's she's done.”

Clinton said she was especially concerned about social media disinformation circulated by Russia, Iran, and China, as well as the pro-Trump media organizations that may pick up any fabricated stories.

"I anticipate there will be a full-court press in October. The digital airwaves will be filled.”

In the age of the 24/7 news cycle, stories affecting the presidential candidates can break at any moment. But October surprises are not a modern phenomenon. Here’s how they’ve influenced elections in the past.

1840: Allegations of election fraud

Though the term was not coined until 1980, the original October surprise came during the 1840 U.S. presidential election, according to POLITICO .

President Martin Van Buren attempted to deploy an October surprise against the Whig Party when he accused top party officials of a “most stupendous and atrocious fraud” in which they paid Pennsylvania voters to travel to New York and cast fraudulent ballots in the state’s 1838 election.

Federal prosecutors, who were members of Van Buren’s Democratic Party, announced the charges against Whig politicians in mid-October. Van Buren hoped the timing of the indictment would sway the election in his favor.

Unfortunately for the Democrat, the electorate didn’t seem to care. Van Buren went on to lose the election to Whig member William Henry Harrison.

1972: Nixon announces Vietnam peace agreement early

During his first presidential campaign, Richard Nixon had promised to end the Vietnan War. By the end of his first term, the conflict was still raging on. But that didn’t stop Nixon and Henry Kissinger, his national security advisor, from prematurely announcing a peace agreement between the United States and Vietnam.

A month before the presidential election, North Vietnamese negotiators agreed to U.S. conditions for peace. But the talks fell apart on October 22. Nevertheless, Kissinger attended a scheduled press conference on October 26 and announced that “peace is at hand.”

The false declaration of peace pushed Nixon further ahead in the polls. He ultimately won the election 12 days later, securing more than 60% of the popular vote. The Vietnam War continued for more than two years after Kissinger’s announcement.

2008: Market crash causes McCain to stumble

Not all October surprises are deliberate or based in deception. In the case of the 2008 race, Republican John McCain was hurt by the stock market crash.

The American public began acutely feeling the effects of the Great Recession in October 2008, when the stock market plunged and the United States was facing a 14-year-high unemployment rate.

The financial crisis put McCain’s candidacy – and his relatability – on even shakier ground. In an August 2008 interview with POLITICO, McCain couldn’t remember how many houses he owned. A month later, CBS News reported , McCain declared that the “fundamentals of our economy are strong.”

The public didn’t agree. Democratic candidate Barack Obama seized on McCain’s gaffes, labeling him as out of touch with everyday Americans. Obama went on to win by nearly 53% of the vote.

Melissa Cruz is an elections reporting fellow who focuses on voter access issues for the USA TODAY Network. You can reach her at mcruz@gannett.com or on X, formerly Twitter, at @MelissaWrites22.

This article originally appeared on USA TODAY: An 'October surprise' could still spell trouble for Kamala Harris, Hillary Clinton warns