In 2016, third-party candidates in the pivotal states of Pennsylvania, Michigan, Wisconsin and Florida won more votes than President Donald Trump's narrow margins of victory.
In Minnesota, New Hampshire and Nevada, those candidates captured enough votes to dwarf 2016 Democratic presidential nominee Hillary Clinton's own slim margins of victory, too.
This year, third-party candidates are struggling to raise funds, are less well-known and are polling beneath their 2016 predecessors — and the unique challenges of campaigning during a pandemic will make reversing those trends nearly impossible.
"I think that there's some good candidates running," Ron Nielson, who managed former New Mexico Gov. Gary Johnson's 2016 Libertarian campaign, said in an interview. "I'm not discounting the candidates running, but they don't have the persona and the charisma has never been developed in those campaigns to capture in the moment. There's just nothing happening."
Four years ago, Trump and Clinton both faced historic levels of unfavorability, opening the door for a more meaningful third-party vote. But the 2020 race between Trump and former Vice President Joe Biden, the Democratic presidential nominee, is different, experts and leading members of both the Libertarian and the Green parties told NBC News.
In some instances, these candidates are not even on the ballot in critical swing states. In Wisconsin and Pennsylvania — two of the most hotly contested swing states this cycle — Green Party presidential nominee Howie Hawkins will not even appear on the ballot.
Still, Hawkins, a longtime Green Party advocate and perennial candidate for office, said there's a simple reason for why the third-party candidacies have not seen the kind of support that was generated in 2016, when they accounted for more than 5 percent of the national vote.
"It's Trump," Hawkins said, adding that he heard similar reasoning when he ran for governor of New York in 2018.
"I had former supporters, donors, phone bankers, canvassers say, 'I got to vote for [New York Gov. Andrew] Cuomo to resist Trump,'" he said. "Which didn't make any, really, electoral sense. But that's, I think, the mentality. That's why it's been difficult for third parties."
NBC News/Wall Street Journal polling data shows that the lack of a competitive third-party candidate may be more beneficial to Biden than to Trump. In interviews with 215 third-party voters in multiple surveys from January through August, the polling found that 2016 third-party voters are breaking toward Biden over Trump by a more than 2-to-1 margin. As the surveys found, 47 percent of those voters are backing Biden while 20 percent support Trump. One-third of that group is either undecided or backing another candidate.
Jeff Horwitt, senior vice president at Hart Research Associates, which conducts the NBC News/Wall Street Journal polls, said last time around those who voted third party "really did not like either candidate."
"And in our research across the year, it's not as though they have great feelings about Biden," he said. "But when you compare their feelings around the questions, positive, negative scales and things like that, Trump's standing is just much, much worse."
The split in this group between those who are now backing Biden and those who support Trump serves as "a really important sign for where things are headed," Horwitt added.
Lack of name recognition could also be a factor. In 2016, the Libertarian ticket featured two former governors, while the Green Party nominated Jill Stein, who had been the party's presidential candidate in 2012. The 2020 third-party and independent field features Hawkins and Libertarian nominee Jo Jorgensen, a Clemson University professor who was the party's vice presidential nominee in 1996. There's also rap mogul Kanye West, who is only on the ballot in a handful of states and has said he is "walking," not running for office, and a collage of lesser-known candidates run as the standard-bearers of tickets like the Constitution Party.
Fundraising provides a snapshot of the tough spot third-party candidates find themselves in this cycle. In 2016, Johnson raised more than $11 million and Stein more than $3 million. This cycle, Jorgensen had raised about $1.4 million as of August, while Hawkins has brought in about $300,000. West has raised just more than $11,000, discounting funds he has provided his campaign, according to the Federal Election Commission.
And while more well-known business executives and politicians ranging from Mark Cuban and Howard Schultz to Rep. Justin Amash, I-Mich., contemplated third-party or independent bids, they opted to stay on the sidelines. Others, like billionaire Mike Bloomberg, who has mulled independent bids in years past, ran in the Democratic primary this year, while former Massachusetts Gov. Bill Weld, Johnson's running mate in 2016, ultimately opted to run against Trump in the Republican primary.
In an interview with NBC News, Weld said the 2020 third-party environment is what it is because "people are scared of Mr. Trump" and "think that he's a dangerous person."
"And so, that would lead many people I think in both those parties, the party of Jill Stein and the party of Gary Johnson to vote for Biden," he said. "Whereas in an ordinary year, they might not vote for the Democrat."
Weld said those invested in the Libertarian movement who backed his ticket in 2016 would not have much of a stomach for Trump, citing what he described as abuses of the Department of Justice, the federal government and law.
Download the NBC News app for breaking news and politics
"The Libertarians are very much conscious of the wise restraints that keep men free and they want to be able to operate within that world," he said. "And Mr. Trump is not really being too subtle about the fact that he would like to remove those parameters of our system of democracy and freedom."
But Nielson said Trump might actually be missing an opportunity to make inroads.
"There's a lot of Liberty movement voters who are somewhat undecided," Nielson said. "I think that there's a lot of them that would probably like to vote for Trump and I think that they're trying to bring themselves in that direction. I think that would be the option that I think a lot of them are probably weighing out is whether they can vote for Trump or not."
Hawkins said he believes Biden will deliver the decisive victory that current polling projects but warned the former vice president will "disappoint" progressives, which Hawkins thinks will give his party new life.
"That's our opportunity. Right now, it's tough for us," he said, adding he hopes 2020 is "just a sort of one-off situation."
"So I think our longer-term prospects are a lot better than the next [few] weeks," he said.