In a race that's already been full of shockers, the biggest one of them all might be if Donald Trump won the White House.
But, in all likelihood, one of the few ways that could actually come to pass would be with the help of a convenient "October Surprise" — a last-minute incident or revelation that can turn on election on its head — or two.
A true "October Surprise," presidential historians agree, must be deliberately timed to influence the outcome of a race. But many other uncontrollable events, like terror attacks and natural disasters, are often grouped into the category due to the profound and unexpected impact they, too, can have on politics.
This year, with national security a prominent issue in the race, terrorism could have an especially large effect on the outcome of the race. And if tragedy were to strike in the late autumn, the result could end up being a surge in support for Trump, who currently trails Clinton in nearly all national and swing-state polls.
"Crisis accrues to the benefit of the strongman. This has always been true in every Western society going all the back to the Roman Empire," GOP strategist Bradley Todd told the Daily News. "Trump would be no exception."
"Historically, unforeseen events in national security and foreign policy arenas shift the political landscape to the Republican nominee," Democratic political strategist Chris Talbot added.
But Trump's erraticness could work against him and disrupt that pattern, Talbot added.
"Trump is not exactly a rock of stability and composure. And in uncertain times, even voters who may not like Hillary Clinton could look towards the former Senator and Secretary of State to steady the ship," he said.
On the other hand, it's impossible to predict how the nominees will respond to crisis until there is one, noted Democratic strategist Rodell Mollineau, who drew on John McCain's performance in 2008.
In late September of that year, during the height of the growing financial crisis, McCain suddenly suspended his campaign and sought to delay a debate with Obama so he could fly to Washington to help Congress work on a rescue plan. He urged Obama to do the same.
"When the financial crisis hit, McCain, who had been the elder statesman, the wise and experienced guy, was the one who freaked out, who became erratic," Mollineau explained.
"And Sen. Obama, the novice, the inexperienced three-year U.S. senator, was the one who looked like a steady hand," he said. "Anything can happen when crisis hits."
McCain had always faced a tough battle to beat Obama, but his campaign never recovered from that gaffe.
If a stock market crash, or a terror attack, or even an Act of God were to hit in late September or October, it would "almost certainly benefit" Clinton because "it comes down to temperament," Mollineau said.
But he also warned Democrats to not underestimate the effect of people voting while scared.
"The fear game has worked for the GOP before," he said, referring to the 2004 George W. Bush re-election campaign that emphasized the ongoing War on Terror and the 1988 race that saw George H.W. Bush pound Michael Dukakis on issues relating to law-and-order.
"Could Donald Trump scare voters into voting for him, should there be an international crisis? Of course," he said.
More likely to occur, however, the trio of strategists agreed, would be continuing revelations pertaining to the controversies surrounding Clinton's use of a private email server and conflicts of interest between her State Department and her family foundation.
"Anything at all that comes out in October, big or little, will be portrayed by the Trump campaign as a bombshell and as a reason not to vote for Hillary Clinton," Mollineau said.
Yet another "October Surprise" wildcard could be Russian involvement in the election.
"I think we are likely to see some degree of Russian meddling," Allan Lichtman, the Distinguished Professor of History at American University, told The News.
"There seems to be pretty credible evidence that they were behind the Democratic National Committee hacks, and the election systems hacks last week in Illinois and Arizona."
"They have a decided preference of Trump. That's well documented. Are they going to release more hacked documents from the DNC that would hurt Hillary two days before the election? Would they hack into the registration systems on Election Day?" Lichtman said.
"Who knows what they might be able to do. It worries me," he said.
While plenty of last-minute events have popped up within range of the last two elections — in 2012, Romney's "47% remark" emerged in late September and Hurricane Sandy happened the week before the election — most presidential historians, including Lichtman, have long cast doubt on the existence of actual October Surprises, with some of the most notable names in the field insisting that the most influential cases involved the ones that never came to pass.
In 1968, for example, Richard Nixon was concerned that his Democratic opponent Hubert Humphrey, the sitting vice president to President Lyndon Johnson, had been trying to finagle a pre-election peace deal to curtail, or end, U.S. involvement in the Vietnam War.
Nixon himself is thought to have used a backchannel to officials in Vietnam to forestall their participation in a peace agreement, telling them they'd get a better deal with him when he was elected.
Neither occurred, Nixon won and the U.S. remained mired in Vietnam for another five years.
Then in 1980, it was rumored that Ronald Reagan was so worried that incumbent President Jimmy Carter might secure the release of the 52 American hostages being held in Iran right before the election, either with negotiations or covert military action — which would have had potentially swung the race for him — that he, some have speculated, may have negotiated with Iranian officials for a release that would occur under his own watch.
As it happened, the hostages were released on Jan. 20, 1981, just moments after Reagan was sworn in as President.
The timing of the release has ever since been under question, but no definitive evidence has ever emerged that Reagan or his campaign worked to delay the release of the hostages.
In 2000, meanwhile, just days before the election between George W. Bush and Al Gore, a Maine Democrat confirmed that Bush had been arrested for drunk driving in the state in 1976.
The incident made many headlines but did little to affect the race.
read more