Chief of a Democratic Super PAC Is Stepping Down

The chairman and chief strategist for a major Democratic outside group is stepping down after eight years, a shift in leadership while plans for 2024 are taking shape for the constellation of entities expected to support Democrats up and down the ballot.

Guy Cecil, who has led that Democratic group, the super PAC Priorities USA, since early 2015, will leave at the end of March, the group announced on Wednesday. It has been a key force in Democratic politics for over a decade, and during Mr. Cecil’s tenure, it became deeply involved in politics beyond presidential races. In the 2022 midterms, it spent heavily on digital ads.

Allies of President Biden are assessing what the support from outside groups for Mr. Biden’s expected re-election campaign will look like. In 2020, officials involved with his campaign indicated that they wanted people to engage with Priorities USA.

It is unclear who will replace Mr. Cecil, but officials said the group has top staff members who have been there for six years. It spent tens of millions on anti-Trump ads in 2020, and it has roughly $11 million in cash on hand and $16 million in further commitments.

“Priorities will continue to lead and grow, and I look forward to watching them take on the fight to re-elect President Biden,” Mr. Cecil said in a statement. “I’m also looking forward to some new adventures of my own and am more committed than ever to making a difference wherever and however I can.”

In recent years, the group has made digital spending a focus, and people close to Mr. Biden are said to envision Priorities as playing a key digital role in the 2024 campaign.

Mr. Biden’s allies expect another outside group, Future Forward, to take a lead in television advertising, two people briefed on the matter said.

Priorities USA was created in 2011, the first of its kind supporting an incumbent president after a 2010 decision by the U.S. Supreme Court involving the conservative outlet Citizens United paved the way.

At the time, it was advised by Paul Begala, a former adviser to Bill Clinton, and led by two former Obama White House staffers, Bill Burton and Sean Sweeney, and it played a key role in establishing a narrative around Mitt Romney, the 2012 Republican nominee and a former businessman, as a heartless corporate executive. The group ran ads in which a man who had worked at a plant that Mr. Romney’s private equity firm pushed to closure foisted blame on the candidate for his wife’s cancer diagnosis, subsequent death and lack of health insurance.

The ads were savage, running in a handful of swing states.

By the next presidential cycle, a number of Democrats saw Priorities as a sustainable vehicle for supporting a different candidate.

Mr. Cecil, a former executive director for the Democratic Senatorial Campaign Committee, took over in 2015, as Hillary Clinton was seen as the front-runner for the Democratic nomination and her allies feared the fund-raising prowess of the presumptive Republican front-runner, Jeb Bush, the former governor of Florida.

In a statement, Mrs. Clinton praised Mr. Cecil, saying he “understood more than anyone that we needed new ways of thinking and communicating to fight back against far-right forces.”

After that campaign ended, the group’s reach evolved and expanded, stretching into dozens of congressional and governor’s races, as well as dozens of other down-ballot races. It raised more than $650 million over those eight years, officials said, and filed 30 voting rights lawsuits.

In 2020, a Priorities ad attacking President Donald J. Trump over his response to Covid prompted Mr. Trump’s campaign to sue a small Wisconsin television station that had aired it. Mr. Trump dropped the suit after he lost the election.

And in 2022, Priorities supported a number of Senate candidates as Democrats expanded their majority in a disappointing midterm cycle for Republicans.