They don’t identify with either major party, they often don’t make up their minds until the last minute, they are difficult to poll ― and in six weeks, some 300,000 of them could help determine whether the nation has to keep worrying about an autocrat winning the presidency next November.

They are New Hampshire’s “undeclared” voters, who are allowed to participate in either party’s presidential primary. Their collective judgement could either put coup-attempting former President Donald Trump on a glide path to the 2024 Republican nomination or lay the groundwork for his defeat in the subsequent primaries.

And although Trump currently leads former South Carolina Gov. Nikki Haley, Florida Gov. Ron DeSantis and former New Jersey Gov. Chris Christie in New Hampshire as he does nationally and in other key states, anti-Trump Republicans say he is clearly beatable.

“Don’t think anything is set in stone yet. Trump’s still the front-runner, but a lot of that support is ‘soft,’ not die-hard,” said Chris Maidment, former chair of the Hillsborough County GOP, who added that voters who plan to vote in the January primary but who are not political junkies are only now starting to pay attention.

“Lots of ‘normies’ won’t choose until after New Year’s or even until primary day,” Maidment said.

Currently, the leading candidate behind Trump is Haley, who has risen in the polls in recent months to surpass DeSantis. Should she win in New Hampshire, she will likely be able to claim a victory in the Nevada primary two weeks later and then head to her home state for what could be a decisive showdown with Trump.

The former president, facing four criminal indictments, nevertheless holds double-digit leads over his remaining rivals for the 2024 nomination in both Iowa and New Hampshire, and even his fiercest GOP critics say his downfall remains a long shot.

“He’s still a heavy favorite,” said former New Hampshire Republican party chair Fergus Cullen. “Nikki has the best shot at consolidating. If DeSantis finishes worse than second in Iowa, he’s done. If Christie then endorses Nikki, that gives her a shot at gathering the ‘not again’ Trump vote and independents in New Hampshire. Still a low odds pattern, but it’s at least possible.”

Still, if Trump is to falter, New Hampshire is the likeliest place for it to begin because its primary is open not only to Republicans, but to the state’s undeclared voters, who again, this election cycle will make up the largest chunk of registered voters. Currently, a full 39% of the state’s 877,571 voters are not registered with either party, while 31% are Republicans and 30% are Democrats.

And according to former New Hampshire Republican National Committee member Steve Duprey, the state’s independent voters have soured on Trump and are ready to move on. While they supported Trump in 2016, they have since then watched Trump lose their state that November and then lose it by an even larger margin four years later.

“Indies do not like Trump,” he said. “Most are coming over to vote against him, I believe.”

Next year, New Hampshire’s “first in the nation” primary comes on Jan. 23, eight days after the caucuses in Iowa ― where Trump also does not have the support of a majority of likely voters.

There, the second-place candidate is DeSantis, with Haley two points behind. Through his supportive “Never Back Down” superPAC, DeSantis has assembled an impressive voter turnout operation, which is often determinative in Iowa.

But New Hampshire voters have notoriously ignored the results from Iowa in recent elections, so it’s unclear what a third-place finish there might mean for Haley or what a narrow win might mean for Trump ― who is essentially running as an incumbent.

“I’m not convinced that the Iowa outcome ever has a significant effect on New Hampshire. Obviously winning is better. But I don’t think there are any New Hampshire voters who would actually change their vote based on the Iowa outcome,” said Jennifer Horn, another former New Hampshire GOP chair. “And history shows us that those who go all in in Iowa rarely see that success propel them forward. Ask [Rick] Santorum and [Mike] Huckabee.”

In any event, New Hampshire’s independents, or “undeclared” voters, as they are officially known, have a storied history of upending front-runners.

In 2000, Arizona Sen. John McCain thumped Texas Gov. George W. Bush, an establishment favorite, 49-30 overall but won independents, who made up a third of the electorate, by a 61-19 margin.

McCain wound up losing the nomination that year, but eight years later, he again won independents 39-27 over favorite Mitt Romney. McCain and Romney were essentially tied, 34-33 with Republican voters, but McCain’s advantage with independents gave him a 6-point overall win and put him on the path for the presidential nomination.

In 2008, those voters accounted for 37% of the primary electorate, but in more recent election cycles that share increased to 47% in 2012 and 42% in 2016, according to exit polling data.

And with the lack of a serious challenge to incumbent Democratic President Joe Biden, independents could make up an even larger share of those voting in next month’s Republican primary. Indeed, nearly 4,000 New Hampshire voters changed their registrations from Democratic to “undeclared” or Republican in the months before the October deadline.

Maidment, who in recent weeks left his job with the Americans for Prosperity Action group after it endorsed Haley and joined the pro-DeSantis superPAC Never Back Down, predicted that the 2024 Republican primary will see 37-38% of ballots come from independent voters.

Duprey predicted an even more independent-heavy electorate: “120,000 Republicans, 130,000 undeclared” ― which if accurate would mean that 52% of ballots in the GOP primary will come from independents.

The entire reason anti-Trump Republicans hold out any hope that Trump remains vulnerable despite his staggering lead in national polls, in fact, is the tendency of such leads to evaporate if the candidate loses the first contest or two.

With so few delegates at stake in the early voting states, the results are more about perceived momentum as both donors and voters try to get behind a winner. A strong performance by a low polling candidate can bring both a flood of interest from voters and campaign contributions from donors. A loss by a dominating front-runner often pierces that assumption of inevitability.

Mike Murphy, a top consultant to McCain in 2000, has been advising listeners of the “Hacks on Tap” podcast he co-hosts for more than a year not to pay any attention to national polling at all until after Iowa and New Hampshire.

He told HuffPost that the best-case scenario is for Trump to lose both contests. The second best case is for him to win only narrowly in Iowa and then lose New Hampshire. However, a loss in Iowa followed by a win in New Hampshire could redound to his benefit, Murphy said.

“If he loses Iowa and wins New Hampshire, he gets a comeback, and he runs the table most likely,” Murphy said. “If he wins Iowa then loses New Hampshire, it’s a problem, but he can survive. Key is he has to lose Iowa and New Hampshire back-to-back. Then he bleeds out.”

And, according to Murphy and others, Haley is best positioned among the remaining non-Trump candidates to use a New Hampshire victory to good effect.

Trump’s efforts to ensure a victory in Nevada, which follows New Hampshire, has led to two separate events: a Feb. 8 caucus run by his supporters in the state party preceded by a state-run primary on Feb. 6. Trump is almost certain to win the caucus, where Christie and DeSantis will also be on the ballot. But his name will not appear on the primary ballot two days earlier, meaning Haley is nearly guaranteed to win that, given that the others who chose to run in the primary, South Carolina Sen. Tim Scott and former Vice President Mike Pence, have both dropped out.

And because the primary will almost certainly have a larger turnout, Haley would be able to boast off a larger mandate from Nevada voters, even if Trump wins all of the 26 delegates, which will be awarded in the caucus.

And the contest after Nevada is South Carolina, where Haley was twice elected governor, is currently running second, and where Trump also has not cracked the 50% mark in polling.

Of course, none of that can happen, anti-Trump Republicans agree, unless Trump either loses New Hampshire outright or wins it only narrowly.

Haley’s strong head-to-head poll results against Biden in the general election will mean little if Trump still seems unbeatable heading into February, Horn said. “Nevada and South Carolina won’t care about them at all if Trump crushes New Hampshire,” she said.