WASHINGTON — The Heritage Foundation, a conservative think tank, has ousted its leader after a power struggle.

The Washington nonprofit’s board of trustees unanimously asked for and received the resignation of Jim DeMint at a meeting Tuesday. The board chairman said in a pull-no-punches statement afterward that “significant and worsening management issues” led to the ouster.

“Heritage has never been about one individual, but rather the power of conservative ideas,” chairman Thomas Saunders III wrote in a statement. “Heritage is bigger than any one person.”

DeMint, a former South Carolina senator, could not immediately be reached.

Rep. Dave Brat, a Virginia Republican, called DeMint’s ouster “a tragedy.”

Dozens of Republican in Congress wrote a love-letter of sorts to DeMint on Monday. They praised him for serving as an inspirational conservative figure “even when confronted by overwhelming opposition, bitter criticism and nagging skepticism.”

Rep. Dave Brat, a Virginia Republican, called DeMint’s ouster “a tragedy.”

“He’s just kind of an ideal person who understood the think-tank world and understands the timing and the strategy along with policy,” Brat said. “And to lose that, it’s incomprehensible. I don’t get it. At all. I don’t get it.”

Some board members called the decision a painful, but necessary, one.

Kay Cole James said it was “purely about management, organizational and structural issues” — not philosophical differences with DeMint.

James said Saunders expressed admiration for DeMint during an all-staff meeting late Monday to announce the leadership change. She added that DeMint had already left the building by then.

Heritage, which has 500,000 members, brought in about $92 million in revenue in 2015 and paid DeMint more than $1 million every year. That’s according to its most recent publicly available tax filings.

The nonprofit has been a crucial ally of President Donald Trump and his still-young administration. The president thanked Heritage — and specifically DeMint — during his speech Friday to the National Rifle Association.

Founder Ed Feulner will serve as president and chief executive officer during a search for DeMint’s replacement.