Ten days after the Nov. 3 midterm elections, around 2,000 Democrats will gather at a Denver concert venue for a conference titled “What’s Next?”Among the headliners will be half a dozen potential 2028 presidential candidates. Two others who aren’t on the official conference program will wield much of the power: hedge-fund billionaires Steve and Sue Mandel.

As Democrats debate the future of their party, the Mandels have quietly poured at least $20 million into political, policy and media projects that are challenging the Democratic establishment and could reshape party politics for years to come.

The Mandels are the chief funders of the group hosting the Denver conference, Majority Democrats, a year-old outfit that has become a proving ground for ambitious young Democratic lawmakers who don’t consider themselves part of the rising far left.

Amid a year full of competing visions for the future of Democratic politics, consultants tried and failed to find a populist superstar in Graham Platner, while supporters of the Democratic National Committee descended into finger-pointing over a botched 2024 election. The Mandels are trying to combine the left’s authentic vibe with centrism’s broad-based appeal.

Critics of the Mandels’ approach call it a “Diet Coke” version of politics, focused more on candidates’ back stories and media savvy than political conviction. The Mandels’ defenders say Democrats need to abandon strict ideology and let candidates embrace a wider variety of views if the party wants to win. The projects and candidates backed by the couple have taken a range of views on the Gaza war, for example.

The couple privately considers themselves liberals on some issues, and Sue Mandel has donated $2.5 million this cycle to the Environmental Defense Action Fund, a group that spent money on some progressive candidates. But they have told allies they believe Democrats need to focus intensely on winning races if they want to change policy.

The Mandels have said little publicly. Candidates benefiting from their money don’t always recognize the megadonor couple when they show up at fundraisers. Operatives who visit their home in Greenwich, Conn., are sometimes surprised by the lack of fanfare: Sue, a college math major who closely follows political news, serves them popcorn.

The couple is taking a “rare, sustained multicycle view of trying to reinvent a party,” said Rep. Jake Auchincloss of Massachusetts, who chairs Majority Democrats.

Politicians involved with the Mandels’ organizations said they have met the couple but don’t hear often from them. Auchincloss estimated he has spoken to the Mandels a half-dozen times while working with the group.

As the movement the Mandels helped fund gains visibility, so do critics from both the party’s left and center, who ask: In a year when the Democratic Party is facing voter revolt over its embrace of elitism, how did a network dreamed up by two East Coast billionaire donors suddenly become a deciding force in determining what makes a winning candidate?

The Mandels’ approach represents the same “Democratic establishment with some new seasoning on top,” said Usamah Andrabi, spokesman for the far left organization Justice Democrats. “That’s simply not what the party’s voters are looking for right now.”Stephen Mandel and Susan Zadek met as students at Harvard Business School and married in 1982. Steve Mandel went on to found his own hedge-fund firm, Lone Pine Capital.

Lone Pine’s strategy involves betting on, and against, stocks and taking stakes in private companies and startups. Since 1997, the firm has generated about $45 billion in net gains for its clients, ranking it among the most profitable hedge-fund managers, according to estimates from Swiss investment firm Edmond de Rothschild.

Its current assets under management are about $20 billion. Lone Pine’s largest disclosed holdings as of the end of June include chip-machine supplier ASML, AI cloud-computing company Nebius Group and Home Depot, according to a regulatory filing.

Over time, Mandel said on a rare podcast interview in 2021, he came to a conclusion: “My highest and best use for better or for worse is trying to take some of that money and make things better for other people.”The Mandels started giving away more than $100 million in some years to education, environmental and other causes, though significant amounts of their philanthropic giving aren’t traceable.

After President Trump won the 2016 election, the couple emerged as political donors to run-of-the-mill Democratic causes. Then they met a political consultant, a onetime Obama aide named Seth London who is based in New York.

During the 2024 election, they experimented with training a handful of up-and-coming politicians. When Trump won, London released a widely circulated four-page memo saying Democrats had become too beholden to an overly ideological left and identity politics.

He called on Democrats to resist calls for free college and healthcare, and reinvest in “our common national identity.”

“The party needs a new alternative faction—a ‘party within the party,’” he wrote. Over the next two years, the Mandels funded that vision into existence. Among their projects:

The Searchlight Institute, a $10 million-a-year think tank, has pitched alternatives to Medicare for All.

Then there is The Bench, an incubator that identifies and helps candidates with compelling back stories. Lis Smith, a Democratic consultant credited with the rise of former Transportation Secretary Pete Buttigieg—who is now affiliated with The Bench—coaches some candidates herself, urging them to be themselves and not simply repeat popular Democratic talking points.

Candidates who had early assistance from The Bench include Texas Senate candidate James Talarico and Nebraska congressional candidate Denise Powell, who are now running competitive races. Bobby Pulido, a former Tejano music star running for Congress in South Texas, said The Bench helped him months before Washington Democrats took notice.

The Mandels follow their races closely, both through public news coverage and in near-constant communication with London, said people familiar with their work.

Sue Mandel was also an early investor in The Argument, a news and opinion website focused on liberalism. “We are totally independent of our investors,” said The Argument founder Jerusalem Demsas, who added that the site has a variety of investors.

Other high-profile individuals have started contributing to Mandel projects. Ex-New York City Mayor Michael Bloomberg is a donor to the super PAC associated with Majority Democrats, for example. So are Kathryn and James Murdoch—the younger son of Rupert Murdoch, who controls News Corp, the The Wall Street Journal’s parent company.

Candidates can also opt to hire operatives who work at The Bench and Majority Democrats to consult on their campaigns via a firm started by London. The arrangement has drawn at least one complaint to federal regulators, from a Republican campaign running against a Bench candidate who alleged it crosses a legal line. (A spokesman for The Bench called the claim “baseless.”) The Bench has also placed some bad bets. During this year’s Senate race in Michigan, it threw its support behind Mallory McMorrow, a telegenic state senator and self-described “pragmatist” who had been a client of Smith’s.

McMorrow dropped out less than a month before the primary, and Abdul El-Sayed, from the party’s left, won. Democrats who didn’t support El-Sayed traded blame. Proponents of The Bench criticized Washington groups for helping the other moderate candidate, Haley Stevens.

A former Stevens adviser had the opposite takeaway: The Bench had made the race more costly and complicated.