A contentious presidential election that's increasingly drawing scorched-earth rhetoric from GOP nominee Donald Trump and Democratic candidate Hillary Clinton has consumers and investors on edge – potentially putting the country's fall earnings season and overall economic health into jeopardy.

The latest consumer confidence index published Tuesday by The Conference Board dropped nearly 5 percent in October to its lowest level since May.

Consumers' assessment of current business and labor market conditions both soured, and their expectations for the future don't look much rosier.

The report comes on the heels of underwhelming consumer spending data from the third quarter. Retail sales consistently fell short of expectations, and with consumer spending accounting for the lion's share of America's overall economic output, that doesn't necessarily bode well for the country's next gross domestic product release.

Tuesday's confidence reading also follows a separate sentiment tracker published earlier this month by the University of Michigan. The university's preliminary Surveys of Consumers report showed a 3.6 percent monthly decline in consumer sentiment in October, while future expectations plummeted more than 7 percent.

One of the leading causes of the decline, Surveys of Consumers chief economist Richard Curtin said in a statement, was "uncertainty surrounding the presidential election."

"Without that added uncertainty the confidence measures may not have weakened [this month]," Curtin said.

Indeed, election uneasiness has been widely cited as a primary concern for U.S. consumers. A report published last month by Bankrate.com found that roughly 6 in 10 Democrats and 7 in 10 Republicans considered the results of the upcoming election to be the "biggest threat to the U.S. economy over the next six months."

A separate survey of more than 1,600 Americans, including more than 1,400 investors, put out this month by financial and investment management company BlackRock found that nearly two-thirds of respondents said the results of the upcoming election will have a large impact on the U.S. economy.

Three-quarters of those surveyed said they believe this election will have a bigger impact on their own financial situation than the 2008 election, while one-third said their financial future faces a threat from the presidential race.

And as nearly two-thirds of respondents said the election has impacted their recent investment decisions, companies, too, are starting to get spooked.

"I think there is just great uncertainty as to what's going to happen in the U.S. – in particular, as a result of the outcome of the election," Greg Creed, CEO of Yum Brands, said during an earnings conference call this month. "It goes without saying that people are sort of trying to decide who to choose and what the impact will be on the economy, and I think people are maybe just hunkering down a little bit."

Arnold Donald, CEO of cruise operator Carnival, recently told investors in a conference call that the company has "anticipated a bit of an election slowdown, as historically there's always been a little fall-off in booking volumes around election time."

Nigel Travis, CEO of Dunkin' Brands, echoed those sentiments in a call last week, saying his doughnut empire has seen an "overwhelming dampening effect of the presidential election."

And Wendy's CEO Todd Penegor was telling investors as far back as August that his company could take a hit from politically anxious patrons.

"When a consumer is a little uncertain around their future and really trying to figure out what this election cycle really means to them, they're not as apt to spend as freely as they might have even just a couple of quarters ago," he said during a second-quarter earnings call, according to CNBC.

What all this means is that companies and analysts have largely set the bar low for performance through the rest of the year, revising down previous sales and revenue projections to account for the widespread political uncertainty.

Emmanuel Hatzakis, a director in the Global Wealth and Investment Management office at Bank of America Merrill Lynch, wrote in a research note last week that he had already seen "some cautiousness in revisions of analysts' earnings estimates in the last month, attributable to uncertainty over the upcoming election."

He said volatility in general isn't entirely outside the norm during a major election year. But corporate revisions, warnings and downgrades may be "especially pronounced" this year, he said, "with so many issues at stake and diverging views between the major party candidates on issues that could impact economic activity and business profitability."

"The bright side is that once the election outcome is known, it could provide a tailwind in the release of pent-up demand in subsequent quarters," he said.

Still, there are some analysts who believe companies could be overselling just how much the election is impacting sales. The beautiful thing about low expectations, these analysts argue, is that they leave little room for disappointment.