Speaker Nancy Pelosi of California has made a pick in her party’s Massachusetts Senate contest, endorsing Rep. Joseph P. Kennedy III in his challenge of incumbent Sen. Edward J. Markey.

The news, first reported by the Boston Globe, comes as voters have already begun to cast ballots in advance of the state’s Sept. 1 congressional primaries. 

“Never before have the times demanded that we elect courageous leaders as today, which is why I’m pleased to join so many of my colleagues in endorsing Joe Kennedy III for Senate,” said Pelosi, according to an email sent by the Kennedy campaign. 

“In 2018, when we took back the House, Joe campaigned across America to make that victory possible and that’s why so many of his supporters are Freshman Members of Congress who Joe helped elect,” Pelosi added. “He knows that to achieve progressive change, you must be on the front lines leading movements of people. Massachusetts and America need Joe Kennedy’s courage and leadership in the Senate.”

Kennedy, a member of the storied political family that also included President John F. Kennedy, took an early lead in the polls, but Markey had closed the gap in recent months.

Still, Markey is among his chamber’s most vulnerable members. The 73-year-old incumbent served 18 terms in the House before moving up to the Senate seven years ago. Kennedy, who turns 40 in October, is in his fourth House term. Few policy differences separate Markey from Kennedy.

In the deeply Democratic state, the primary is the real election, as whomever wins it is nearly assured the Senate seat. 

Some of the party’s progressive stars, including New York Rep. Alexandria Ocasio-Cortez and Massachusetts Sen. Elizabeth Warren, have lined up behind Markey. Ocasio-Cortez cut an ad for Markey earlier this summer. 

Though it was quickly eclipsed by Pelosi’s endorsement, liberal group Democracy for America said Thursday it was backing Markey. 

“In 2020, our country needs strong, tested leaders that progressives can trust to fight for social, racial, economic, and climate justice in the U.S. Senate and, in the Senate primary in Massachusetts, that leader is Senator Ed Markey,” said the group’s CEO Yvette Simpson in a news release. “From his early leadership in the fight against climate change to his co-sponsorship of the Green New Deal with Congresswoman Alexandria Ocasio-Cortez, Sen. Markey has been a bold, visionary progressive leader in the fight for climate justice and against environmental racism.”

Markey ended June with a cash-on-hand edge over his challenger, $4.8 million to $4.2 million.