Tuesday’s New Hampshire state primary could end up being a referendum on Trump’s chances to win the state

The New Hampshire primary provides the starkest New England test of Republican feelings toward President Trump this year. Trump has made himself a titillating subplot in the Republican primaries for Senate and in the First Congressional District, where the winner will take on Pappas.

In June, Trump took to Twitter to endorse Brian “Corky” Messner to be the Republican nominee for Senate. Trump also endorsed a former Republican operative and State Department official, Matt Mowers, as the candidate to take on Pappas, who is serving his first term in Congress.

Trump’s pair of endorsements gave each primary race definition after months of obscure Zoom campaigning. Beyond the size of their campaign bank accounts, where Messner and Mowers held advantages, there was no real sense of who was actually winning.

The Trump endorsement was the most important moment in the campaign for both of them. Trump’s endorsement in GOP politics is pretty much all-powerful. For most of 2020, Trump had a perfect record of 64-0 in endorsements in a Republican primary; if he endorsed, his candidate won.

Trump often chooses not to endorse either, particularly if the race isn’t that competitive in the general election or if the Republican primary itself is too close or too complicated. Trump has not endorsed in the competitive primary in New Hampshire’s other House district, where the winner will take on Kuster. And in the region’s only other high-profile Republican primary, Trump didn’t endorse Dale Crafts in Maine’s Second Congressional District until after Crafts won a tricky three-way primary.

Trump’s perfect streak in 2020 ended with a pair of upsets in Virginia and North Carolina on June 23. If that happens in New Hampshire, it could have implications for the presidential race there.

After all, polls suggest New Hampshire is a uniquely fertile ground for Republicans who don’t support Trump. Because of that, candidates who wanted to oppose Trump in a primary basically rooted their campaigns in the state. In the end, nearly all dropped out for financial reasons, and how New Hampshire Republicans broadly feel about Trump was never tested during the February New Hampshire presidential primary.

However, the duo of races he did get involved with are perfectly binary. Each features two major candidates, one Trump backed and one Trump did not. (To be clear, all of the major candidates themselves say they support Trump, even those who didn’t get his support in return.)

Polling is very limited in these primaries heading into next week, though Senate candidate Don Bolduc’s campaign is the one aggressively attacking Messner as if he were the front-runner. The same is true for Mowers’s opponent, Matt Mayberry, who used precious time during his closing statement at the only televised debate to go after what he said were omitted portions of Mowers’s personal financial disclosure forms.

Trump has shaped each contest in just two endorsement tweets. Mowers, the House candidate, began his first-ever television ad with the words “endorsed by President Trump” and Messner, the Senate candidate, has a closing campaign ad that is basically just Trump talking about Messner during a New Hampshire rally last week.

What might really help these candidates aren’t just the tweets, but that Trump has put his Republican National Committee to work on behalf of these candidates, with phone banking and door knocking. This remains a very controversial and possibly unprecedented move, given the party’s tradition of remaining neutral in primaries.

But there are other factors in the contest. For starters, both Mowers and Messner are being accused of carpetbagging. Mowers, who worked in the state to lead Chris Christie’s campaign, only came back to New Hampshire in 2018 and announced a run. This is also roughly what Messner did; he has lived in Denver most of his life and even formed his New Hampshire Senate exploratory campaign in Colorado.

If Trump’s candidates lose these races, it could speak to problems within his own campaign for president in this swing state. Trump has trailed in every New Hampshire poll of his reelection since he narrowly lost the state in 2016. It’s not just that some Republican voters may choose the other guy for whatever reason, but that Trump’s get-out-the-vote operation also lost.

With so much at stake in the general election, Trump’s campaign could decide that what happened on Tuesday is a reason to either double down on their efforts to win New Hampshire, or just walk away and focus on bigger states.

James Pindell can be reached at james.pindell@globe.com. Follow him on Twitter @jamespindell.