Independent Alan Caron withdrew from the governor’s race Monday and urged his followers to vote for the Democratic candidate, Attorney General Janet Mills.

His decision fulfills a campaign trail promise to get out of the race if it became apparent he could not win. 

“I’m not a person who quits things easily,” Caron said at a Portland news conference. “Today I’m writing the final lines in this chapter of my life.”

He was then joined at the podium by Mills, whom he described as “the only one who can bring us forward.”

Mills thanked Caron for the endorsement, saying: “This event is all about pulling together. … We are going to win this together.”

Caron, who has trailed in last place the entire campaign, made a pledge in a March 23 op-ed column in the Portland Press Herald he would exit the race by mid-October if it were clear he could not win.

Polls have shown Mills and Republican Shawn Moody strongly leading the race to succeed Gov. Paul LePage, with Caron, an economic development consultant, and fellow independent Terry Hayes, the state treasurer, trailing far behind them — typically in the single digits.

Given his standing in the polls, Caron had been under increasing pressure over the past week to honor his pledge. 

Although Hayes did not get Caron’s endorsement, she appealed to his supporters to vote for her.

“Electing another partisan Democrat or Republican as governor guarantees more fighting and gridlock in Augusta,” Hayes said in a statement Monday.

“Maine can’t afford four more years of what didn’t work before and what isn’t working now.” 

Caron, a former Democrat, said there was “no possibility” he would endorse anybody other than Mills, adding that the two campaigns started talking about this outcome several weeks ago after a debate.

“I think we have to deal with practical realities,” Caron said, when asked why he endorsed a party-backed candidate instead of independent Hayes.

“I am not going to win this race. Janet is going to win this race, and I want to be a part of making that happen. I wish things had gone differently.

“I do think we’ve had too much partisan gridlock and I’m persuaded Janet can help break that gridlock.”

In addition to support from Caron, Mills acquired backing Monday from a much higher-profile politician: Hillary Clinton. The former Democratic presidential candidate tweeted an endorsement early in the day, describing Mills as “an experienced leader and an outstanding public servant. …”

Moody campaign adviser Brent Littlefield responded to Caron’s announcement on Twitter, saying the move was “not a surprise” given Caron’s prior activism as a Democrat. Littlefield noted Hayes had also been a Democrat.

“If someone wants politics as usual they can pick Mills or Hayes,” Littlefield tweeted. “Maine people want a fresh voice with a proven history of creating jobs and solving problems, and that is why entrepreneur Shawn Moody will be elected as Maine’s next governor.”

Hayes has promised to stay in the race until Election Day. On Monday, she released a five-point economic plan that includes seeking Legislative approval for $8 million to recruit workers, a “match” to the $8 million the state spends promoting tourism; lowering the state income tax to 5 percent from the current three-tier system ranging from 5.8 percent to 7.15 percent, depending on income level; developing a statewide wellness plan to lower health care costs; seeking $100 million in annual bonding for four years to expand broadband; and, replacing the current state education funding formula with a statewide teachers contract with the state paying all teachers’ pay and benefits.

Caron has come under increasing pressure from the left to drop out in order to avoid the split electorate that lifted the current Republican governor, LePage, to victory in the 2010 governor’s race with just 38 percent of the vote.

In LePage’s first win, independent Eliot Cutler came in second with 37 percent of the vote and Democrat Libby Mitchell finished a distant third with 19 percent. In his re-election victory, LePage got 47 percent of the vote, Democrat challenger Mike Michaud got 44 percent and Cutler got 8 percent.

At his news conference, Caron was asked if he thought Hayes also should withdraw from the race.

“I’m not going to suggest what she should do,” he said. “I hope only that she will find a few moments away from the vortex of the campaign and think about what she could do best to move the state forward.”

Caron and Mills both said they wished ranked-choice voting was being used for the governor’s race. For the Nov. 6 general election, ranked-choice voting will be in place only for federal elections: The Senate race and both House races. It will not apply to the governor’s race or to any state legislative races because of constitutional concerns.

In his op-ed piece last spring, Caron called on nonviable candidates to “do the right thing” and withdraw from the race.

“If a candidate clearly cannot win the election by mid-October, they need to put the interests of Maine ahead of themselves and pull out. No wishy-washy stuff,” Caron wrote in a March 23 op-ed in the Portland Press Herald. “No arguments that major party candidates have special privileges. Just do the right thing.”

A Waterville native, Caron, 66, dropped out of high school in ninth grade but would go on to start his own printing and design business in Portland. He eventually earned a master’s degree in public administration from Harvard University’s Kennedy School of Government, and became a consultant to businesses, nonprofits and government leaders.

In 2003, he founded the nonprofit GrowSmart Maine, which worked with the Brookings Institution to produce a report, “Charting Maine’s Future,” that identified Maine’s strengths and weaknesses as officials sought to revitalize the state’s economy.

The report, which was widely cited at the time, recommended preserving Maine’s “quality of place” while streamlining government, cutting taxes, investing in the state’s areas of economic strength and following “smart growth” principles.

More recently, Caron formed Envision Maine to work with businesses, government and nonprofits on ways to improve the state’s economy. He also was a freelance columnist for the Maine Sunday Telegram/Portland Press Herald.

As a gubernatorial candidate, Caron did not seek public campaign funding, instead running a largely self-financed race. Caron raised a total of $785,660, with $56,350 in contributions and $725,000 in loans to himself. 

Caron’s name will still appear on the ballot, but any votes for him will not be tabulated.

Alan Caron reflects on a question Monday during a press conference at the Portland Public Library, where he endorsed Janet Mills for Governor. (Shawn Patrick Ouellette/Portland Press Herald)