AUGUSTA, Maine — Maine Senate President Mike Thibodeau dropped out of the Republican gubernatorial primary on Monday, becoming the highest-profile candidate to leave the race so far and reducing his party’s field to four ahead of the June election.

Thibodeau made the announcement in a Facebook post, citing his leadership position in the Legislature and business obligations as reasons for leaving the race, saying “there just isn’t time to do all of these things and run for governor at the same time.”

Thibodeau came up in Maine politics as a steady social conservative, but he has become best-known for recent battles with Gov. Paul LePage, a fellow Republican who is looming over the intraparty race to pick his successor.

Their relationship soured in 2015 as lawmakers readied to pass a two-year budget over LePage’s veto. Just before then, Lauren LePage, the governor’s daughter, placed robocalls into Thibodeau’s district, criticizing him for “working behind the scenes with liberal Democrats.”

Things worsened two years later, when House Republicans allied with LePage to block a compromise budget between Senate Republicans and Democrats, forcing Maine’s first government shutdown since 1991. In January, LePage declined to endorse a candidate to replace him, but he said he didn’t support Thibodeau.

All of that made Thibodeau’s primary run in today’s Maine Republican Party a difficult one. A poll last year said that LePage had a 79 percent approval rating with Republicans in the state.

The other candidates in the race — businessman Shawn Moody, former Maine Health and Human Services Commissioner Mary Mayhew of South China, Maine Senate Majority Leader Garrett Mason of Lisbon Falls and Maine House Minority Leader Ken Fredette of Newport — have attached themselves to the governor in varying degrees.

LePage’s chief strategist and the governor’s daughter work on Moody’s campaign. Mayhew often touts her work as LePage’s lieutenant on welfare issues. LePage signed Mason’s 2011 bill to establish charter schools — a signature accomplishment for both politicians. Fredette’s caucus has been key to LePage’s power in Augusta.

The Maine Democratic Party tweeted that the Republican race is now “LePage vs. LePage vs. LePage vs. LePage.”

Thibodeau declined an interview through Robert Caverly, his chief of staff. But Bob Emrich of Plymouth, a pastor and evangelical leader who co-chaired Thibodeau’s campaign, said Thibodeau told him Monday that he was going to drop out.

Emrich “wasn’t in agreement,” saying Thibodeau had momentum and that this is “a loss for Maine.” He said Thibodeau was “concerned” about some “mean-spirited” politicking during the race from some Republicans who seemed motivated by LePage’s criticism of Thibodeau. He said some questioned his conservative credentials when he supported the candidate.

“It’s unfortunate and it’s not good for the party,” he said. “I think there’s a lot of diversity in the Republican Party … and I think that that makes for healthy debate and discussion, but not if we’re trying to shut everybody down who disagrees with us.”

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Michael Shepherd

Michael Shepherd joined the Bangor Daily News in 2015 after three years as a reporter at the Kennebec Journal. A Hallowell native who now lives in Augusta, he graduated from the University of Maine in...