FOR DECADES IT has served as a winning argument for electing Republican governors in deep-blue Massachusetts: A Republican in the corner office is a sensible check on the impulses of the Democratic-dominated Legislature. 

In January, however, that equation will be scrambled for only the second time in 32 years, with Democratic attorney general Maura Healey poised to take the reins as governor alongside a Legislature where Democrats wield power with overwhelming supermajorities. 

On paper, that should make for harmony-filled days on Beacon Hill. But it hasn’t always worked that way, as one-party rule can also bring new challenges and potential for internecine conflict. 

Deval Patrick’s two terms as governor, from 2007 to 2014, mark the only time Democrats have controlled both branches of government since Michael Dukakis left office more than three decades ago, at the start of 1991. 

“Generally, when you have the same party in power in the executive and legislative branch, there certainly is broader philosophical cohesion, but from our experience, each branch takes its role seriously and is proprietary about that,” said Tim Murray, who served as lieutenant governor under Patrick, a Beacon Hill outsider who had his share of conflicts with lawmakers. 

While there may be greater philosophical cohesion when the governor and legislative majority come from the same party, it can make it harder to establish who takes the lead in putting forward legislative priorities. That has led to no small amount of Beacon Hill chatter over the years of mostly divided government that Democratic leaders of the House and Senate actually like that arrangement.

“The conventional wisdom for decades has been that Democratic legislators have better relations with Republican governors, because politically they’re in charge in a way that isn’t true when a Democratic governor is in office and in charge,” said Jim Aloisi, a longtime player in Democratic politics who served as transportation secretary under Patrick

Lou DiNatale, a veteran Democratic strategist and pollster, said a Democratic governor may have an expectation that Democratic legislative leaders will take cues from them. Under a  Republican governor, DiNatale said, “If I‘m Speaker or Senate president, he’s got to negotiate with me every goddamn day. If it’s a Democratic governor, they come to me with something I have to do every day. The governor gets to tell me I need to whip the Democrats into line and pass these three important things that I know are going to cause me problems in my caucus.”  

One-party rule combined with lopsided margins in the Legislature can also cause more tension within the House and Senate because legislation proposed or supported by the governor doesn’t need a veto-proof supermajority, setting the stage for potential division among Democrats in each chamber. 

Senate President Karen Spilka said Democrats don’t always see eye to eye on every issue, but she dismissed the idea that Democratic lawmakers work better with Republican governors. “I am excited to see a Democrat back in charge of the governor’s office in Massachusetts,” Spilka said. “I’ve known and worked with the governor-elect for a long time. We are aligned with each other on a lot of our values. I know from past experience that Maura Healey is a good partner in communicating and getting things done.” 

Good relationships and collaboration, say Beacon Hill veterans, are often more important than agreement on every policy detail. 

It’s a lesson Dukakis says he learned the hard way. The only person to ever serve three four-year terms as governor in Massachusetts, Dukakis said in his first term he was a much better talker than listener when it came to dealing with the Democratic-led Legislature. 

“I kind of woke up to that fact after getting my head handed to me,” he said of the crushing Democratic primary defeat he suffered in 1978 when seeking reelection after his first term in office. 

Dukakis came back to win the governor’s office four years later and was then easily reelected to a third term. In those two later terms, he said, “every time we came up with a new policy, we created working groups,” which included lawmakers, to flesh out the ideas. “I became a better consensus builder,” he said, “and we managed to get a hell of a lot done.” 

“My hope is that Maura and company will do a good job of building relationships with the Legislature and getting things done,” Dukakis said of Healey.

Although she won office as attorney general eight years ago against the insiders’ favored candidate, Healey is now “a known commodity” with established relationships on Beacon Hill, said Aloisi, which he said bodes well for her tenure. The mindset of many lawmakers, he said, is “you have to quote-unquote ‘pay your dues.’ That’s a short way of saying, are you one of us?” 

Patrick, a former Justice Department official in Washington who had never run for office before, was very definitely not one of them when he arrived on Beacon Hill after winning the governor’s office in 2006 as a crusading, progressive outsider. 

He bumped heads with then-Senate President Robert Travaglini a month before even taking office. In December of 2006, Travaglini told a meeting of a business group that he had criticized Patrick in a private conversation they had for vowing to cut hundreds of millions of dollars in waste from state government, something Travaglini felt was an insult to the Legislature. He said Patrick backed away from the idea in their conversation. 

Travaglini, the Globe reported, told the business group he told Patrick they would get along well if the new governor collaborated with the Senate. “If not,” Travaglini said, according to one attendee who spoke with the paper, “I have senators across the state who share my vision and my approach, and if forced to choose, I’m comfortable with whom they’ll choose.” 

Murray, Patrick’s lieutenant governor, said the uneasy encounter was “like a hazing,” to show the incoming administration “how this thing works.”   

Patrick notched more than a few accomplishments together with the Legislature, including a $1 billion life sciences initiative, major transportation restructuring, and several big energy and environmental measures. But he never seemed to find his groove in cultivating relationships, in many ways the lifeblood of Beacon Hill. That boiled over when Patrick introduced a sweeping tax package in his 2013 State of the Commonwealth speech without giving legislative leaders any heads-up on the proposal, a slight that helped doom the plan. Lawmakers slashed back the package by more than two-thirds. 

Sometimes, however, conflict emerges over straightforward differences on issues, despite the shared party affiliation. 

“The Democratic Party does not suffer from groupthink, whatever else you think of it,” said Jesse Mermell, who served as Patrick’s communications director in his second term. 

When the administration proposed a transportation package at one point that included a 19-cent increase in the gas tax, the cold shoulder from lawmakers was not a consequence of being kept out of the loop as the plan was developed. “We kept them pretty well briefed,” said Aloisi. “They just didn’t like it.” 

John McDonough, who served in the House during the end of the Dukakis reign and the first years of Republican Bill Weld’s administration, said the unique challenges that come from one-party rule are real, but so are the opportunities it creates. “In terms of the actual policymaking, I think on the big things there’ll be more consistency than not, and the differences will be less consequential,” said McDonough, now a professor at the Harvard T.H. Chan School of Public Health. “But disagreements and conflict are the nature of the work.”

Mariano, who was an early supporter of Healey, endorsing her in March, two months after she announced her candidacy, said he’s eager to collaborate with the new governor. “I was proud to support governor-elect Healey’s historic campaign, as I know she is committed to building a better Massachusetts for everyone,” the Speaker said in a statement. “I look forward to working with the Healey-Driscoll administration on addressing the most pressing issues facing the Commonwealth.”

Though Healey and legislative leaders have said they want to take up tax relief in the new session that begins in January, exactly where else their agendas will align or part is unclear. Healey, who faced no opposition in the Democratic primary and little competition in the general election, largely steered clear of specifics in the campaign. 

“The question always becomes, what’s the governor’s agenda?” said DiNatale. “What are you going to do, what are you going to ask the Legislature to pass? This is when the rubber meets the road.”

Those questions, said McDonough, remain unanswered. “The campaign, in terms of discussion of issues, has been a complete nothing-burger,” he said. “There’s just nothing to chew on.” 

As for how the state’s return to one-party rule under Healey and incoming Lt. Gov. Kim Driscoll will play out, Spilka said she’s unsure – but optimistic. 

“In a few months, I’ll be able to give you a better answer,” she said. “But I’m excited about the energy that I believe Maura and Kim bring to the jobs for the Commonwealth, and the ability we’ve had to work together in the past.”