Portside

The leaders of two of the nation’s largest and most influential labor unions have quit their posts in the Democratic National Committee in a major rebuke to the party’s new chairman, Ken Martin.

Randi Weingarten, the longtime leader of the American Federation of Teachers and a major voice in Democratic politics, and Lee Saunders, the president of the American Federation of State, County and Municipal Employees, have told Mr. Martin they will decline offers to remain at-large members of the national party.

The departures of Ms. Weingarten and Mr. Saunders represent a significant erosion of trust in the D.N.C. — the official arm of the national party — during a moment in which Democrats are still locked out of power and grappling for a message and messenger to lead the opposition to President Trump. In their resignation messages, the two union chiefs suggested that under Mr. Martin’s leadership, the D.N.C. was failing to expand its coalition.

Both labor leaders had supported Mr. Martin’s rival in the chairmanship race, Ben Wikler, the chairman of the Wisconsin Democratic Party. Mr. Martin subsequently removed Ms. Weingarten from the party’s Rules and Bylaws Committee, a powerful body that sets the calendar and process for the Democratic Party’s presidential nominating process.

In her resignation letter, dated June 5 and obtained on Sunday evening, Ms. Weingarten wrote that she would decline Mr. Martin’s offer to reappoint her to the broader national committee, on which she has served since 2002. She had been on the Rules and Bylaws committee since 2009.

“While I am proud to be a Democrat, I appear to be out of step with the leadership you are forging, and I do not want to be the one who keeps questioning why we are not enlarging our tent and actively trying to engage more and more of our communities,” Ms. Weingarten wrote in her resignation letter to Mr. Martin.

Ms. Weingarten is an influential figure in the Democratic Party and the leader of a union that counts 1.8 million members.

Mr. Saunders, whose union represents 1.4 million workers, declined his nomination to remain on the D.N.C. on May 27, his union said on Sunday.

“The decision to decline the nomination to the Democratic National Committee was not made lightly,” Mr. Saunders said in a statement to The New York Times. “It comes after deep reflection and deliberate conversation about the path forward for our union and the working people we represent.”

His statement seemed to echo Ms. Weingarten’s critique, suggesting the D.N.C. was becoming an inward-looking body that failed to innovate.

“These are new times. They demand new strategies, new thinking and a renewed way of fighting for the values we hold dear. We must evolve to meet the urgency of this moment,” Mr. Saunders said. “This is not a time to close ranks or turn inward. The values we stand for, and the issues we fight for, benefit all working people. It is our responsibility to open the gates, welcome others in and build the future we all deserve together.”

Mr. Martin has recently faced scrutiny and criticism from within the party. His leadership was openly challenged by David Hogg, a party vice chairman who announced he would fund primary challenges to sitting Democrats — an action long considered out of bounds for top party officials.

Mr. Hogg announced last week that he would not seek to retain his post after the party voted to redo the vice chair election, after it had been challenged on an unrelated technicality.

Notably, Ms. Weingarten had endorsed Mr. Hogg’s primary efforts, saying it was necessary to “ruffle some feathers.”

On Friday, during an appearance at the Center for American Progress in Washington, Gov. Tim Walz of Minnesota, a longtime Martin ally, said he still had confidence in him but regretted the public squabbling.

“I certainly wished we wouldn’t have dirty laundry in public, but you know the personalities, things happen,” said Mr. Walz, who endorsed both Mr. Martin and Mr. Hogg in the party elections this year. “I don’t think Ken’s focus has shifted one bit on this of expanding the party.”

Mr. Martin did not immediately respond to messages about the resignations. A spokeswoman declined to comment.