A battle over the importance of endorsements has broken out among GOP candidates for governor.

Challenger Mike Minogue’s campaign says the long list of endorsements racked up by competitors Mike Kennealy and Brian Shortsleeve mean very little, if anything.

Former Republican nominee for governor and senate Geoff Diehl, who’s backing Minogue, tells the Herald that getting out to meet and gather input from voters is much more valuable.

“Endorsements didn’t decide my races, and they won’t decide this one. Mike Minogue isn’t running to impress political elites. He’s running to listen to the people of Massachusetts,” said Diehl, who recently delivered his own endorsement to Minogue. “While the other campaigns chase Beacon Hill approval and questionable supporters, Mike is building something real with voters.”

Minogue has been hitting the pavement since launching his campaign, holding meet-and-greets and other events across the state. The GOP megadonor hasn’t been shy about using his wallet either, donating millions to his campaign and spending early on TV advertisements

Diehl, who had unsuccessful bids for Massachusetts Senator in 2018 and Governor in 2022, says Kennealy and Shortsleeve are “political insiders,” adding that success at the state Republican convention isn’t always earned by a long list of endorsements.

“The point we’re trying to make in this cycle is you’ve got two candidates who are political insiders who seem to think pushing out endorsements from politicians is important. It doesn’t necessarily translate to success at the convention. In fact, I think the opposite — the more you’re actually out there meeting with people and taking input from actual citizens, which is what Mike’s doing every day, the more successful you’re going to be,” said Diehl, pointing to a recent Minogue event.

“Mike just had an event down on the Cape with over 200 people. Mike is inviting the average Massachusetts citizen to weigh in and tell him what’s important, rather than trying to take the advice of Beacon Hill insiders,” he said.

But Minogue’s rivals are pushing back.

Kennealy Campaign Communications Director Logan Trupiano says Minogue is “disrespecting voters,” calling out Minogue for his past donations to Democrats as well as recent comments he made on WBUR, where he seemed to distance himself from the Republican Party, among other things.

“Mike Minogue is a mega donor to Ed Markey and the Massachusetts Democratic Party who, by his own admission, feels no association with the Republican Party that he joined a few months ago for the sole purpose of running for Governor and seeing himself on TV,” Trupiano said.

“After months of declining invitations to meet the grassroots, he’s now telling moderators he needs at least six more months of coaching before he’s ready to stand on a debate stage with Mike Kennealy.  Minogue should stop claiming he will be a ‘new kind of Governor’ because there is nothing new about disrespecting the intelligence of voters – Maura Healey does it daily,” Trupiano said.

As for the Shortsleeve campaign, strategist Holly Robichaud says Minogue is simply “frustrated” that his spending on campaign advertisements have not translated to success.

“Brian Shortsleeve is winning support across the Commonwealth because he has a proven record of reforming government, balancing budgets, cutting costs and creating jobs. He will make Massachusetts affordable by slashing Maura Healey’s insane taxes, fees and regulations…Mike Minogue is frustrated because he spent millions of dollars on television to say nothing and wonders why he isn’t making any progress with his campaign,” Robichaud told the Herald.

“If Republicans are going to defeat Healey, it’s going to take more than a big checkbook. We need to offer a stark contrast and a better path forward, not a fainter version of her happy talk,” she said.

Diehl’s criticisms come as the Shortsleeve and Kennealy campaigns continue to garner support. Last week, the two candidates announced a lengthy list of new endorsements, with Kennealy boasting 22 new endorsements with Shortsleeve announcing another 14 for himself.

The Minogue camp’s criticisms, however, don’t stop at the push to highlight endorsements.

Diehl said the backing collected by Minogue’s competitors is a result of insider connections through their past work in the Baker Administration. Shortsleeve was the MBTA’s first-ever Chief Administrator from 2015-2017, while Kennealy served as former Gov. Charlie Baker’s Secretary of Housing and Economic Development.

“Mike got into this without insider connections. He’s a self-made, successful businessman who is never going to be beholden to cutting deals on the campaign trail or in office. He’s spending his time listening to voters — not chasing the approval of Beacon Hill,” Diehl said. “Mike is letting actual citizens tell him what matters. The other campaigns are pushing out endorsements from the same political insiders who’ve been running this place for years.”

Mingoue, Kennealy and Shortsleeve will face off in the Republican primary in September.

Brian Shortsleeve (left), a venture capitalist and a former MBTA official, and Mike Kennealy (right), a former state cabinet secretary, are both running for governor of Massachusetts as Republicans. (Herald file photos)