Chaos has erupted at a conservative think tank after it was revealed that one of its new donors is Len Blavatnik, the Ukrainian-born billionaire who owns the Warner Music record label.

Charles Davidson — the founder of the Hudson Institute’s Kleptocracy Initiative, a group dedicated to exposing threats by authoritarian regimes to US democracy — said he quit as its executive director upon learning that the Hudson Institute had accepted a $50,000 donation from Blavatnik.

“Russian kleptocracy has entered the donor pool of Hudson Institute,” Davidson said in an exclusive interview with The Post. “Blavatnik is precisely what the Kleptocracy Initiative is fighting against — the influence of Putin’s oligarchs on America’s political system and society — and the importation of corrupt Russian business practices and values.”

Blavatnik — long friendly with bigwig politicians like Bill Clinton and movie makers like Martin Scorsese — made his fortune in the controversial privatization auctions of 1990s post-Soviet Russia, scooping up valuable aluminum companies on the cheap.

Since then, Blavatnik has aggressively sought respectability in the West. In addition to buying Warner Music, Blavatnik has donated more than $100 million to Oxford University and $50 million to Harvard.

On Tuesday, a spokesman for Blavatnik referred questions to the Hudson Institute, whose remaining directors and advisers appeared to side with their new donor.

“The Blavatnik Family Foundation sponsored a table to our annual gala. We are grateful for all those who are supporting Hudson’s work tonight,” the Hudson Institute said in an emailed statement.

However, Ilya Zaslavskiy, an Oxford-educated policy wonk who also sits on the Kleptocracy Initiative’s advisory council, griped that Blavatnik’s business partners Viktor Vekselberg and Oleg Deripaska have been sanctioned by the US government.

“Blavatnik is an oligarch,” Zaslavskiy told The Post, using a term that has long drawn strenuous objections from Blavatnik’s public relations team.

“It’s amazing how Blavatnik converts philanthropy into political access and influence,” Zaslavskiy said, adding, “It’s a philosophical question: Can you do good things with bad money?”

The fracas emerged ahead of the Hudson Institute’s annual gala in New York on Monday, which honored outgoing House Speaker Paul Ryan — who accepted an award via video — and departing UN Ambassador Nikki Haley.

Blavatnik did not attend, but at Monday’s event, Haley harshly criticized Russia for seizing three Ukrainian ships last month, calling the move an “outrageous, blatant provocation.”

The Hudson Institute most recently made headlines in August, when its computers were attacked by elite Russian hackers known as Fancy Bear.

At the time, Hudson Institute’s president and chief executive, Ken Weinstein, told Fancy Bear in a Wall Street Journal op-ed to “get stuffed.”