Pressley could help Warren build support among black voters, who could be pivotal in the 2020 election, political observers said.

A dynamic speaker who has built a national profile in less than a year in Washington, Pressley could be a powerful surrogate for Warren, whom she will join on the campaign trail Thursday in North Carolina.

US Representative Ayanna Pressley, a rising progressive star and the first black woman to represent Massachusetts in Congress, announced Wednesday she is endorsing Senator Elizabeth Warren for president, delivering a major boost to the Cambridge Democrat as she faces growing attacks from her political rivals.


“In the Democratic primary, women of color have the potential to be a decisive constituency in determining the nominee,” said Brian Fallon, who was press secretary to 2016 Democratic presidential nominee Hillary Clinton.

“There are probably few surrogates that any of these candidates could enlist that would be more dynamic, more compelling in reaching those voters, than Ayanna Pressley.”

Pressley has the potential to be a powerful validator for Warren, who has vied for the top position in polling with former vice president Joe Biden but failed to chip away at his support from the black community.

“This is exactly what the campaign needed. It could be the thing that helps her break free from the pack,” said Aimee Allison, founder and president of She The People, a national network mobilizing women of color in politics.

Pressley’s endorsement is not entirely surprising, given their shared Massachusetts roots and their longtime cooperation.

When Warren first ran for US Senate, Pressley, then a Boston city councilor, was the first elected official to endorse her. And though Warren did not endorse Pressley’s 2018 primary challenge to incumbent Michael Capuano for the Seventh District seat, she did remain neutral, while most of the Massachusetts congressional delegation backed the incumbent.


But Pressley was not among the first to join Warren’s campaign for president, and until Tuesday, her endorsement was the subject of widespread speculation.

In supporting Warren, she broke with three other progressive freshman lawmakers who make up the “Squad” — Representatives Alexandria Ocasio-Cortez of New York, Ilhan Omar of Minnesota, and Rashida Tlaib of Michigan — and who recently endorsed Senator Bernie Sanders of Vermont, giving his campaign a major boost.

Ayanna Pressley and the rest of the “Squad.” Associated Press/File

“It’s smart politics for Ayanna,” said Mary Anne Marsh, a Boston-based Democratic strategist, who noted that, if Warren were to leave office for the White House, “that is a big leg up for Ayanna if she wants to run for that Senate seat.”

She also noted that Pressley’s endorsement video highlighted the nexus of the two women’s values.

In the video, Pressley says Warren’s plans are about power, “who has it, who refuses to let it go, and who deserves more of it. For Elizabeth and for me, power belongs in the hands of the people.”

“The American people deserve to be represented by elected officials who see them, who listen to them, and who fight for them,” Pressley says. “This election is a fight for the very soul of our nation. Elizabeth knows how to fight and she knows how to win.”

Pressley also works hard for those she endorses, Marsh noted, pointing to the many events she attended with candidates she supported in Tuesday’s election.

Among them: Boston City Councilors Michelle Wu, Annissa Essaibi-George and Kim Janey and candidates Kenzie Bok, Julia Mejia, Alejandra St. Guillen, and Ricardo Arroyo.


Warren also recently claimed the endorsement of Suffolk District Attorney Rachael Rollins, another woman of color, who appeared with Warren in South Carolina and touted her understanding of the disparities people of color experience.

“Unequivocally, I think she gets it,” Rollins said in a video endorsement she posted on Twitter.

Such supporters may be helpful to Warren as she tries to make inroads over Biden, beloved for his work beside the nation’s first black president, Barack Obama. Warren also faces competitors US Senators Kamala Harris and Cory Booker, who are black.

Because Warren, Biden, and Sanders have been ranking closely in polls, the difference could come down to their “ability to inspire greater numbers of women of color,” Allison of She the People said.

“That’s going to be the secret sauce.”

Pressley’s endorsement comes as Warren faces criticism from across the political spectrum over her Medicare for All plan.

Biden has also sharpened his attacks against her, calling her condescending and elitist in a blog post while also taking a swipe at her for once being a registered Republican.

By contrast, Pressley’s endorsement video and accompanying statement stress Warren’s focus on people from all walks of life, especially the most vulnerable.

“Elizabeth listens to the voices of community; in church basements and in packed gymnasiums, she has heard the stories of families who are struggling, and she has responded with activism, visionary policies, and community-led plans,” said Pressley, who represents the most diverse congressional district in Massachusetts.


Pressley, known as a powerful speaker, is also the most valuable type of campaign surrogate — one who can draw a crowd on her own, Fallon said.

“She is a very buzzed-about figure,” he said.

He noted that Pressley, who has filed a resolution to impeach Supreme Court Justice Brett Kavanaugh, recently spoke at an event he hosted for his new organization, Demand Justice, a progressive advocacy group for the federal courts.

“She had people hanging on her every word,” Fallon said.

Warren’s endorsement is the highest-profile one Pressley has made so far. Last month, she backed Jesse Mermell, a Brookline selectwoman running to succeed Joseph P. Kennedy III in the Fourth District as he runs for Senate against Senator Edward J. Markey, a fellow Democrat. Pressley has signaled she has no intention of endorsing a candidate in that primary.

Victoria McGrane can be reached at victoria.mcgrane @globe.com. Follow her on Twitter @vgmac. Stephanie Ebbert can be reached at Stephanie.Ebbert@globe.com. Follow her on Twitter @StephanieEbbert.