Republican front-runner Donald Trump picked up a major Maine endorsement about a week before the state’s Republican presidential caucuses. But the backing of Gov. Paul LePage failed to translate into a win for the billionaire businessman and reality TV star.

Instead, Maine Republicans overwhelmingly went for Texas Sen. Ted Cruz.

LePage’s anointment of Trump is one of many examples this election season of just how little Republican voters heed endorsements from party insiders. The same goes for Democrats. An endorsement from New Hampshire’s Democratic governor, Maggie Hassan, didn’t prevent former Secretary of State Hillary Clinton’s double-digit loss to Vermont Sen. Bernie Sanders during the Granite State’s primary last month.

The influence of endorsements has never been a given, but the strong anti-establishment mood this campaign season on both side of the aisle has blunted any influence from endorsements, according to Jeffrey Selinger, a political scientist at Bowdoin College.

With endorsements falling flat, do they even matter? That depends on the election and the voter. But when it comes to presidential nominating contests, the endorsement of a governor isn’t likely to change any candidate’s political fortunes.

When a governor’s backing doesn’t matter

Whether they’re running for office at the local, state or federal level, candidates covet gubernatorial endorsements with the hope that governors’ political and fundraising machines will lock in wins. The impact on individual voters, however, is less clear cut.

Voters weigh a seal of approval from their governor more heavily than a newspaper or celebrity endorsement, according to a 2007 Pew Research Center survey, in which 37 percent of respondents said an endorsement from their governor would influence their vote compared with 25 percent for an endorsement from Jon Stewart, former host of “The Daily Show.”

A governor’s endorsement, though, doesn’t sway all votes in the same direction. Only 19 percent of respondents said they were more likely to vote for a presidential candidate with the governor’s seal of approval versus 18 percent who said the endorsement would diminish their support.

In Maine, LePage isn’t the first governor whose endorsed candidate performed poorly at caucus time. In 2008, then-Gov. John Baldacci endorsed then Sen. Hillary Clinton ahead of the Maine Democratic caucuses. She went on the lose to then-Sen. Barack Obama by nearly 20 points.

When a governor’s backing does matter

Some political scientists suggest governors can better influence political fortunes when they weigh in on small local and state elections.

In a 2011 paper, Richard Vining and Teena Wilhelm, political scientists at the University of Georgia, concluded that when a governor endorses candidates in judicial elections — unlike Maine, 38 states elect judges — the endorsement has a huge influence on the outcome of the vote. A governor’s high profile has a more meaningful impact on judicial elections because those races usually are less visible than presidential contests, Vining and Wihelm wrote.

“When individuals have little information, as is often the case in judicial elections, they rely on cues and information shortcuts to construct their preferences,” they wrote.

But during presidential elections, voters are inundated with information about candidates from national media outlets and other sources, so when the governor anoints a candidate it has little impact on which way voters lean.

“It’s a useful thing if you’re a strong supporter of the governor, but I just don’t know if that’s going to drive the electorate in this information-rich environment,” Vining said.

The party doesn’t decide

Political scientists have long considered the “invisible primary” — the largely behind-the-scenes competition among presidential candidates for the support of influential party leaders — a litmus test for a campaign’s viability.

The 2008 book “ The Party Decides” concluded that in elections between 1980 and 2004 when the political elite coalesced around a particular candidate, rank-and-file voters followed suit. “Early endorsements in the invisible primary are the most important cause of candidate success in the state primaries and caucuses,” the book’s authors wrote.

But with Republicans and Democrats coalescing around party insurgents and anti-establishment outsiders, the backing of the political elite has become practically toxic.

Just consider Florida Sen. Marco Rubio, who leads the Republican field in terms of endorsements from within the Beltway as well as several Republican governors, including Sam Brownback of Kansas, Asa Hutchinson of Arkansas and Nikki Haley of South Carolina, according to FiveThirtyEight’s 2016 endorsement tracker.

Rubio has been unable to leverage this institutional support into primary victories. He lost Kansas, Arkansas and South Carolina by 31 points, 8 points and 10 points, respectively.

On the other hand, Trump, who has the fewest endorsements of any standing Republican candidate, leads the nomination race by 99 delegates over Cruz, according to The New York Times. Of the 11 Republican governors who have so far made endorsements, just Greg Abbott of Texas backed the candidate (Cruz) who won his state’s primary. Cruz, of course, had the homefield advantage.

On the Democratic side, Clinton has scooped up dozens of endorsements in Congress and statehouses across the country, and she enjoys a wide margin in the delegate race against Sanders. But endorsements from Democratic governors in New Hampshire, Vermont, Colorado and Minnesota did little to prevent her double-digit losses to Sanders in those states’ nominating contests. Only in Virginia did the Democratic governor (Terry McAuliffe) endorse the candidate (Clinton) who won his state’s primary.

“‘The Party Decides’ thesis thus far appears to be failing the 2016 presidential election nominating season test,” Selinger, the political scientist at Bowdoin College, said.

Meanwhile, anti-endorsements from party insiders also have done little to influence nominating contest outcomes. Ahead of the Iowa caucus, Republican Gov. Terry Branstad urged Iowa voters not to support Cruz because of his hostile stance toward ethanol subsidies; on caucus day, Iowa went to Cruz. In Massachusetts, Republican Gov. Charlie Baker took a firm stance against Trump, who nonetheless captured nearly 50 percent of that state’s GOP vote.

There’s another explanation for why these endorsements have failed to shift the political winds: Most endorsements from the political elite simply came too late to make a difference, according to Marty Cohen, a political scientist at James Madison University and one of the writers of “The Party Decides.”

Endorsements from governors can make a difference if they come months in advance of primaries because governors often wield effective political and fundraising machines. But when that endorsement comes a week in advance of when voters choose their parties’ nominees — as with LePage’s endorsement of Trump — it leaves little time to put that influence to work.

“The real failure this election season was the elite in the party not making a concerted effort early on to rally around a candidate,” Cohen said.