The State House in Augusta, as seen from Capital Park.

AUGUSTA, Maine — The new year will kick off with the peaceful transition of Maine’s governorship from Republican Paul LePage to Democrat Janet Mills on Jan. 2.

For the first time since 2011, one party will control both the executive and legislative branches, and Maine will send two Democrats to Congress for the first time since 2014. The state’s political dynamics changed dramatically in 2018 and here are half a dozen situations that bear monitoring next year.

Mills and legislative Democrats will take control. Can they afford to fulfill the campaign promises they made? There’s no question that the new governor will be different than her predecessor and Democrats can aggressively advance their agenda in 2019 under Mills and legislative majorities. There are questions about how much, how quickly and how to do it without a backlash.

Mills isn’t a particularly liberal Democrat. Her opponents in the 2018 Democratic primary beat her up from the left with help from progressive groups, including the Maine People’s Alliance, which will try to push a paid sick leave program through the Legislature this year.

Mills has been cagey on that issue. She has vowed to implement Medicaid expansion that LePage has blocked and must find a way to fund it and other priorities with the Legislature, but she has also said she won’t raise taxes on Mainers in her first two-year budget proposal.

Michael Saxl, a Democratic lobbyist and former House speaker, said House Majority Leader Matt Moonen, D-Portland, will have “the hardest job in the State House” in managing Democrats with “pent-up demand for action” and helping them “focus those great ideas.”

Jason Savage, the executive director of the Maine Republican Party, said the No. 1 way for Mills to trigger a “rebellion” in her first term is to “break her promise on taxes.” With only a little power in Augusta, that’s what Republicans will be policing with their voices next year.

How long will LePage’s specter loom over Maine politics and who will emerge as leader of the Maine Republicans? The outgoing Republican said just before Election Day he’s going to “retire and go to Florida.” But he says he’ll oppose Mills in 2022 if she doesn’t govern to his liking, telling WVOM this month he has “taken a baseline of every department” to monitor her.

The Maine Republican Party lost the governor’s race, the 2nd Congressional District and the Maine Senate in 2018 and that could prompt a leadership fight against Demi Kouzounas, who was named chair of the party last year with LePage’s endorsement.

Her likeliest challenger may be former Senate Majority Leader Garrett Mason, who said Monday he’s considering a run. Kouzounas didn’t respond to a request for comment, but she told the Portland Press Herald in November that she hadn’t decided whether to run again. She kept the party’s staff intact. Mason, the runner-up in the 2018 gubernatorial primary, may make changes.

LePage referenced this situation in the WVOM interview, blaming outgoing Republican legislative leaders — including Mason — for 2018 losses and saying some “want to run the party” and “shame on them.” Even if he never runs again, LePage won’t be a quiet ex-governor.

Who will emerge as Democrats’ favorite to challenge Maine’s senior senator? In 2018, Sen. Susan Collins was the subject of intense Democratic ire after the moderate Republican’s October support for U.S. Supreme Court Justice Brett Kavanaugh. She also backed her party’s tax cut plan in 2017 after opposing their earlier bids to repeal the Affordable Care Act.

Polling showed Maine Republicans may have soured on her after she preserved the Affordable Care Act. Now, liberals have raised nearly $3.8 million for her eventual 2020 opponent behind a massive organizing push around Kavanaugh. Polling has since showed her support may have reshuffled along party lines.

House Speaker Sara Gideon, D-Freeport, and Susan Rice, the former U.S. ambassador to the United Nations, are among the well-known Democrats publicly considering runs so far, though Gideon hasn’t run beyond her liberal legislative district and Rice doesn’t live in Maine full time.

Collins is still formidable, but Democrats don’t see her as invincible anymore after she won a fourth term with 68 percent of votes in 2014, so she’s certain to get a well-funded opponent if she runs for a fifth term. Formal campaigns against her should begin next year.

Can Maine’s new Democratic congressman make himself relevant? Rep.-elect Jared Golden, the Democrat who beat outgoing U.S. Rep. Bruce Poliquin of Maine’s 2nd District, will be sworn in on Jan. 3 without legal challenges hanging over his head after Poliquin’s Monday move to dismiss a lawsuit over Maine’s system of ranked-choice voting.

Golden, a Marine veteran, has pledged to oppose House Minority Leader Nancy Pelosi, D-California, when she likely ascends to the speaker’s chair. He told the Sun Journal that he asked leaders to consider him for assignments on committees overseeing taxes, defense, transportation and education. He’ll embark on a listening tour of the district in late January.

He figures to be a top target for Republicans in 2020 after a race in which campaigns and outside groups spent a record sum of more than $20 million. Poliquin adviser Brent Littlefield said there was “nothing to report” on the outgoing congressman’s political or private plans until then.

For once, it looks like 2019 won’t be the year of the referendum. During the LePage era, Democrats who were often stymied by the governor turned to the ballot box. Transformative measures were passed, including same-sex marriage, Medicaid expansion, marijuana legalization and ranked-choice voting.

But now, one party will control Augusta and it may make the referendum process less relevant. Similar efforts to at least two of the three referendums that advocates are gathering signatures for now — the paid sick leave effort from the Maine People’s Alliance and another one looking to legalize doctor-assisted suicide — will be tried in the Legislature this year.

If they fail, both efforts could be go on either to the 2019 or 2020 ballot, though Valerie Lovelace, who chairs the “death with dignity” effort, said advocates are targeting 2020 if they must go to referendum.

A third potential referendum — a conservative effort to pass a state law banning female genital mutilation that had been targeted for June — seems to have fizzled for now.

Portland’s one-term mayor will continue his fight with city councilors — this time probably at the ballot box. In 2015, Ethan Strimling easily beat Mayor Michael Brennan with endorsements from the local chamber of commerce and 11 of 17 city councilors and school board members — all of whom Brennan had angered as the city’s first elected mayor in 88 years. Strimling now looks a little bit like Brennan, albeit with more organization behind him.

He has warred with City Manager Jon Jennings and drawn harsh rebukes from city councilors who he has often pushed from the left, floating a proposal for a citywide paid sick leave program. In May, the CEO of the Greater Portland Chamber of Commerce hit the mayor in a Portland Press Herald OpEd blasting the sick leave proposal as “a far-reaching mandate.”

Strimling, who has declared to run again but hasn’t committed to it yet, is positioning himself for re-election as a bit of a movement Democrat. A December email to supporters courted donations while saying the chamber was among the “business interests … attacking my record.”

If he runs, he will likely face a difficult re-election challenge in 2018 from within City Hall. Councilors Spencer Thibodeau and Justin Costa said on Monday that they’re considering runs. Councilor Belinda Ray didn’t respond to a request for comment, but she may also run.

BDN writer Jake Bleiberg contributed to this report.

Michael Shepherd joined the Bangor Daily News in 2015 after time at the Kennebec Journal. He lives in Augusta, graduated from the University of Maine in 2012 and has a master's degree from the University...