NEWBURYPORT, Mass. — Massachusetts Attorney General Maura Healey said Tuesday she will take Donald Trump to court to prevent the Republican president-elect from imposing his “unconstitutional agenda” on the state and nation.

Speaking at a town hall meeting in Newburyport, the Democrat ticked off a list of Trump’s pledges that she plans to fight, such as eliminating federal funding for Planned Parenthood and his nomination of Oklahoma Attorney General Scott Pruitt, who has questioned climate science, to head the U.S. Environmental Protection Agency.

“This administration really concerns me,” Healey told a crowd of hundreds at City Hall. “We need to stand up to it.”

On the stage behind her, a projection screen displayed Healey’s campaign signs with pronouncements urging people to “Stop Republicans from defunding Planned Parenthood” and calling on Congress to reject Trump’s nomination of Alabama Sen. Jeff Sessions for attorney general.

With Trump set to move into the White House in little more than a week, Healey is positioning herself as a leading voice of opposition in deep-blue Massachusetts, taking on his promises to deport immigrants, rollback energy and environmental regulations, and repeal the Affordable Care Act.

Healey, who backed Democrat Hillary Clinton for president, referenced a 2009 lawsuit she worked on under former Attorney General Martha Coakley that successfully challenged the federal law defining marriage as a union between a man and woman.

“If we have to sue the federal government, we’ll do it again,” she said.

Political observers say Healey’s role as the state’s top law enforcement official gives her a visible platform from which to launch criticism of Trump’s unpopular policies.

“There’s a major role for state attorney generals to check federal power; it’s a tactic Republicans have used for years,” said Erin O’Brien, associate professor and chair of the political science department at the University of Massachusetts at Boston. “And Maura Healey is incredibly well positioned to become a national voice for how states can combat the Trump agenda.”

Healey has leveraged the president-elect’s fiery statements in fundraising pitches. “If Donald Trump plans to roll back much of the progress we’ve made in Massachusetts and as a nation, I will do everything in my power to stop that,” she said in a recent email to supporters.

Currently, she has more than $800,000 in her campaign account, with nearly $300,000 of that raised since the Nov. 8 election, according to the Office of Campaign and Political Finance.

Healey, of Charlestown, is the nation’s first openly gay attorney general. She was elected in 2014 to replace Coakley, a Democrat who challenged Gov. Charlie Baker for governor that year.

Since taking office, Healey has gone after the National Rifle Association over loopholes in the state’s assault weapons ban that allowed the sale of “copycat” weapons.

She also joined other attorneys general to file a legal challenge against Exxon-Mobil over allegations that it knew and misrepresented the connections between its fossil fuel products and climate change.

Those efforts have won praise from supporters and liberal groups but scorn and legal challenges from gun owners and the oil industry, who’ve accused the lawyer of overstepping her authority.

Healey’s political maneuvering has also fueled speculation that she is gearing up to challenge Baker for the governor’s office in 2018.

She has dismissed talk of running for governor.

Observers said if Healey chooses to run, she would pose a formidable challenge to Baker, who remains a popular chief executive among Republicans and many independent voters.

“How she plays her role in the Trump era will be crucial in determining whether she wants to move up to higher office,” O’Brien said.

“But two years is a long time,” she added. “A lot could happen between then and now.”

Christian Wade covers the Massachusetts Statehouse for the North of Boston Media Group’s newspapers and websites. Reach him at cwade@cnhi.com.