It’s a high-profile endorsement for Warren at a time when the vast majority of big-name Democrats are hanging back and waiting to see how the ever-expanding field shakes out.

Kennedy will announce his support for Warren in a speech introducing her Saturday, they said. He is expected to focus heavily on economic issues and detail Warren’s efforts in that space, arguing that her record sets her apart.

Representative Joseph P. Kennedy III, heir to that famous Democratic dynasty, plans to endorse Elizabeth Warren’s bid for the 2020 Democratic presidential nomination at her announcement Saturday in Lawrence, according to people familiar with the event.


Also on Saturday, Warren will also be endorsed by Senator Edward J. Markey, a Malden Democrat and the first US senator to endorse a Democratic candidate for 2020, according to a person familiar with his plans.

Freshman Representative Lori Trahan, who represents the Third Congressional District that includes Lawrence, will also announce she is supporting Warren, an aide said.

The three will be among the first sitting members of Congress to formally back any of the declared 2020 candidates. Representatives Ted Lieu, Katie Hill, and Nanette Barragán of California have all endorsed Senator Kamala Harris of California, who officially announced her candidacy last month.

Kennedy’s support also represents a significant vote of confidence in Warren from one of the party’s rising stars at a time when she can use it. Her fledgling campaign experienced a fresh bout of turbulence this week after a new document surfaced, showing, in her own handwriting this time, another instance in which she identified herself as Native American.

Throwing his political capital behind Warren will set pundits’ tongues wagging for another reason: Kennedy is good friends with former representative Beto O’Rourke, a potential 2020 aspirant. Kennedy campaigned for O’Rourke in 2018 as the Texas Democrat attempted to unseat conservative Senator Ted Cruz in a bid that captured national attention but ultimately failed. O’Rourke said this week that he will make an announcement about his 2020 plans later this month.


Does Kennedy know something about O’Rourke’s plans that the rest of us don’t? If not, Kennedy’s endorsement shows that Warren’s decision to get into the primary early may have helped her head off competition in the battle for high-profile support and top staff, which prominent backers can help attract.

Kennedy introducing Warren in Lawrence echoes the program from the 2016 Democratic National Convention, where Kennedy was the opening act for Warren’s prime-time speech. That time, Kennedy told a humorous story about arriving unprepared for the first day of Warren’s class at Harvard Law School and how she called him out for it.

Kennedy has recently been pushing what he calls “moral capitalism,” an agenda that dovetails with economic themes Warren has long championed and is making a centerpiece of her presidential campaign. In a speech at Harvard Law School earlier this month, Kennedy laid out a list of federal policy initiatives to address the country’s worsening economic inequality, ranging from paid family leave to a revamped tax system.

“Americans spend their days fighting each other over economic crumbs — while our system quietly hand delivers the entire pie to those at the top,” Kennedy told New England business leaders back in November.


The grand-nephew of the last president from Massachusetts, Kennedy attracted some 2020 speculation of his own. In 2018, party leaders tapped him to deliver the Democratic response to President Trump’s State of the Union.

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