The board of the Heritage Foundation requested the resignation Tuesday of president Jim DeMint. (Alex Brandon/AP)

The board of the Heritage Foundation on Tuesday ousted president Jim DeMint after days of turmoil and internal debate, blaming him for management and communication problems that have roiled the venerable conservative think tank.

Thomas A. Saunders III, chairman of the Heritage Foundation’s Board of Trustees, said in a statement that the 22-member board unanimously requested and received the resignation of DeMint, the firebrand former senator from South Carolina. Heritage founder Ed Feulner will serve in his place until a permanent successor is chosen.

“After a comprehensive and independent review of the entire Heritage organization, the board determined there were significant and worsening management issues that led to a breakdown of internal communications and cooperation,” Saunders said. “While the organization has seen many successes, Jim DeMint and a handful of his closest advisers failed to resolve these problems.”

In his own statement, DeMint called the critique “puzzling,” saying the board had praised his work for the past four years and approved annual performance bonuses for the entire management team.

He said he was proud of his work at Heritage, citing accomplishments such as the think tank’s role in helping lead President Trump’s transition team.

“I will continue to be part of that great fight for freedom for years to come,” DeMint added.

The decision was announced at the conclusion of an hours-long, closed-door meeting in which the board contended with deep disagreements among its members that resonated beyond the organization’s Capitol Hill headquarters.

Unhappiness with DeMint among Heritage board members began shortly after the former senator took over the think tank in 2013, a move that coincided with the departure of some longtime academic researchers. At the same time, DeMint won applause in some quarters for increasing the organization’s political clout and outreach to grass-roots conservatives.

Trump’s election initially appeared to vindicate DeMint’s approach. Heritage served as a policy and staff pipeline for the Trump campaign and the transition, helping provide a blueprint for the White House’s 2018 budget proposal. Last week, during a speech to the National Rifle Association, Trump personally thanked DeMint and Heritage for supporting the confirmation of Judge Neil M. Gorsuch to the Supreme Court.

While the alliance with Trump raised the think tank’s profile, it also repelled some ideological conservatives who did not view Trump as consistently compatible with conservative traditions.

The dissatisfaction with DeMint, fueled by several factors, came to a head this month as his contract came to an end. Among the issues was tension between DeMint and Feulner, his predecessor, who was concerned that the DeMint-era emphasis on political activism overshadowed the institution’s role in the intellectual development of the conservative movement, according to people familiar with the situation.

DeMint also reportedly clashed with Michael Needham, chief executive of Heritage Action for America, the organization’s advocacy arm, whose pugilistic approach alienated some congressional Republicans and GOP leaders.

But board trustee Bill Walton said the issue was not “Needham versus DeMint.”

“It’s boring old management stuff,” said Walton, saying that excessive bureaucracy prevented papers from getting approved rapidly and scholars from getting permission to attend meetings. “We think we can make it leaner and more effective.”

Since its founding in the 1970s, Heritage has been one of the preeminent purveyors of conservative ideas in Washington. The think tank’s annual budget of more than $80 million is equal to those of the Cato Institute and the American Enterprise Institute combined.

After DeMint took over, however, some Republicans chafed at the organization’s new focus on political advocacy, particularly its targeting of GOP members. Heritage Action led the charge against President Barack Obama’s signature health-care law, in some cases pressuring lawmakers to vote against funding the government to prevent funding for Obamacare, a maneuver some GOP leaders saw as self-defeating.

On Tuesday, Saunders said the decision to part with DeMint was “difficult and necessary,” adding that “it will make Heritage stronger in the short term and the long run.”

Longtime Heritage staffers predicted the current dispute would pass quickly.

“Heritage is a strong institution that has been here since the 1970s,” said Brian Darling, a senior official at Heritage for seven years before leaving to join the staff of Sen. Rand Paul (R-Ky.) “Jim DeMint did a tremendous job launching attacks on Obamacare and helping to confirm Justice Gorsuch. The organization changed under his leadership in ways that made some people uncomfortable. But the changes were in the margins and the organization will still stand strong and prosper in the future.”

Alice Crites contributed to this report.