Voters said they didn't want a Biden-Trump rematch. Now they're facing longest general election ever.

For a while, poll after poll suggested voters didn't want a rematch between Joe Biden and Donald Trump -- let alone one that took most of the year.

But now voters are likely to get just that, after they ended up turning out in support of both of candidates in the early nominating races, setting up a general election campaign whose length could be virtually unheard of in modern history.

"It's almost a cruel joke on the electorate that the longest presidential election potentially ever might also be the one that they're least excited about," said one Democratic pollster, speaking anonymously to candidly discuss the race.

Technically, the nomination fight only began in mid-January with the Iowa caucuses. But since then, the field of candidates has narrowed down to just Biden and two long shot challengers, Rep. Dean Phillips and author Marianne Williamson, on the Democratic side; and Trump and former U.N. Ambassador Nikki Haley among Republicans.

Both Biden and Trump easily won the few contests held so far and both hold huge leads in other primary polling, per 538's averages.

And while the nominating races will continue for months before the nominations are officially awarded, Biden and Trump are already focusing on one another as though the general election has begun.

That could mean months and months of major swing-state stumping, millions of dollars in ads filling the airwaves, reams of daily headlines and protracted battles between the two candidates, their campaigns and their surrogates.

Having a general election race essentially kick off some nine months before Election Day in early November would set a new precedent in modern politics, experts said. The closest recent parallels are in 1996 and 2000, when the nominating contests were essentially over by March -- but the nation was also less polarized and much less sour on the two top choices, adding another layer to voters' unease.

"I can think of no case where it's been settled as rapidly as it has been right now," said presidential historian Mark Updegrove, who forecasted the race could get "dirty."

"And I think that Americans don't have much of a stomach for that," Updegrove told ABC News.

Analysis has found the number of crossover voters dropping over time and surveys also paint a conflicted portrait of attitudes on Biden and Trump as their respective parties' nominees.

More than half of adults in an Associated Press-NORC Center for Public Affairs Research poll last month said they'd be dissatisfied with that outcome, though three out of four Republican-leaning adults said in a more recent ABC News/Ipsos poll that they would be very or somewhat satisfied with Trump as the GOP's presidential nominee.

More broadly, Biden and Trump continue to face negative approval and favorability ratings, according to 538.

Interviews with voters throughout the election cycle so far have painted a picture of an electorate seemingly in disbelief -- and, sometimes, dread -- that the two 2020 presidential nominees could again find themselves on top of the 2024 ballot.

"I don't know, yet," Helene Hagar of Raymond, New Hampshire, told ABC News earlier this month when asked who she'd choose in a hypothetical rematch. "It's a tough decision, because I'm not at all happy in the direction that the country is going."

"It's scary," Mas Kono told ABC News in Charleston, South Carolina, referring specifically to Trump's rhetoric.

Kono said he had voted for both Democrats and Republicans but generally favored Democrats. "I wish there were better candidates rather than more candidates," he said.

"I haven't made a decision yet," said South Carolina Democrat Georgie Koss, who is looking for a new candidate to support. "I just think that we need somebody young and fresh, lots of new ideas."

Yet battle lines are already being drawn up as Biden and Trump begin blitzing the campaign trail.

The current president has been traveling to swing states and other places with key Democratic demographics like South Carolina, campaigning on messages around abortion access, as he did in Virginia; defending democracy, as he did in Valley Forge, Pennsylvania, this month; and touting his economic record, as he did when he accepted the endorsement of the Michigan-based United Auto Workers last week.

After keeping a fairly light schedule for much of 2023, Biden in recent months has made trips to North Carolina, South Carolina, Wisconsin and more while Vice President Kamala Harris and their campaign surrogates have gone even further afield -- a pace that is anticipated to get even more frenetic as the long calendar ahead begins to shorten.

"I think that it is contrast in its truest form, which is that we'll be hammering Trump on his record but also touting a lot of what the president has done," said one Biden campaign aide, who was not authorized to speak publicly about election strategy.

Looking ahead to the next nine months, the aide said, "The how is, to some degree, all the normal things that you would expect."

"We have leadership and staff in every battleground at this point, that'll continue to grow. We expect to have thousands of field organizers by the summer," this person said. "So -- strong battleground presence, lots of door knocking, we have been airing paid TV and advertising already. That'll continue to ramp up more and more."

Trump, for his part, is leveraging his 91 indictments and spree of court appearances to rally his supporters to his side while arguing that Democrats are out to get him. (He has pleaded not guilty and denies all wrongdoing; prosecutors say they aren't politically motivated.)

Trump's message of persecution and retribution, on top of openly questioning Biden's stamina and fitness, are expected to be at the core of his campaign, highlighted at what are expected to be a spree of his signature mega-rallies.

"President Trump has said over and over again in meetings with individuals and with larger groups that the campaign is not going to be playing prevent defense. It's all offense all the time," said one source in Trump's orbit, who wasn't authorized to speak publicly about his campaign.

"That means rally after rally after rally," this person said. "The tip of the spear of the Trump offense strategy is the very personal nature of these rallies."

Still, outside experts said, the campaigns could also face headwinds navigating a historically long general election along with voters -- trying to ensure they time their messaging just right, without being exhausting or being ignored.

"When you run any campaign, the key to victory is not peaking too early. He needs to be peaking in late October, not in August. He needs to be peaking in late October, not in June. And when the campaign runs this long, that is the risk, that you peak too early," the source in Trump's orbit said. "They know that this is a three-act play, and we're only in the second act. So they get it, totally. So, they're going to schedule these things to a crescendo."

"It's a good question," Karen Finney, a Democratic strategist who worked on Hillary Clinton's 2016 campaign, added when asked how campaigns can make sure they don't bog down (or turn off) voters over nearly a year of stumping. "We don't know because we've never done it before."

Other operatives, though, disagreed that the candidates risk oversaturating voters in the months to come given that both Biden and Trump already boast near-universal name recognition and dissatisfaction with presidential politics right now appears so high. A lengthy election season wouldn't change those factors.

"Donald Trump is in the news and has been in the news daily for decades, really, but in politics since 2015, which is nine years. So that's not new. And Joe Biden is the president. He's in the news every single day. That's not news. I don't see what a 10 month-campaign changes as far as the way it's received by the country. I mean, these are two guys who are saturated in news coverage already. What does the campaign change?" asked one Trump campaign alum.

Yet one thing most experts who spoke with ABC News agreed on -- a nearly 10-month general election just may not be good for the country.

"You see with the U.K. and Canada and other developed nations that they deliberately limit the campaigns, I think in part to keep people more engaged, so that people aren't turned off and tuned out," Updegrove, the historian, said. "I think we would be wise to do that. I think, on balance, it's bad for the country to have toxicity like this, as it's bound to be, for as long as it's going to play out."

ABC News' Gabriella Abdul-Hakim, Libby Cathey and Hannah Demissie contributed to this report.