The Roosevelt coalition agreed by and large with the direction of Sanders’s economic program, but they regretted the crudeness of his exposition. They understood, for example, the appeal of a call to break up the banks but found greater sophistication in Clinton’s proposals to regulate “shadow banking.” They wished his advisers had been more careful with the numbers. And the personal iconoclasm and moral purity of the Sanders campaign didn’t lend themselves to governance. How, given the way Obama’s ideals foundered on a kind of Washington default mode, did Sanders plan to staff an entire administration?

Wong and her allies spent a lot more time worrying about Donald Trump than they did valorizing Sanders. Their fear was, and is, that Clinton’s response to Trump’s faux populism, racism, xenophobia and misogyny — that we needed to make America not “great” but “whole” again — would crowd out everything she once said about corporations and inequality. Clinton’s central economic metaphor, “ladders of opportunity,” promised access to the current system rather than a wholly different one. But Roosevelt has found that a message of “leveling the playing field” polls much better with voters of color and the white working class. (Its recent follow-up to “Rewriting the Rules,” a paper about race by the fellows Dorian Warren and Andrea Flynn, acknowledges that the economic interests and political needs of the two constituencies may not always seem perfectly aligned.) The central preoccupation for Wong, and for Silvers and for Warren, was to demonstrate that it was the courageous thing, not the cautious one, that would capture the preponderance of the electorate.

It is common, in Washington, to view yourself as there by some celestial accident; Beltway insiders delight in a good sneering reference to Beltway insiders. But Wong really does seem like an improbable person to preside over a think tank. She grew up in Silicon Valley, studied poetry at Stanford, got a Ph.D. in political science at Berkeley, worked as a high-school teacher and then at a valley start-up and then happened into a job at the Democracy Alliance, a semi-secretive club of progressive donors. She can barely bring herself to utter the phrase “think tank,” much less “policy shop.” Late one evening in Washington, we walked by a thickset monolith that glowed with a cold marmoreal light, as if James Turrell had built a fortress for some paranoid ice king. The front read CSIS: the Center for Strategic and International Studies. Wong rolled her eyes, theatrically shuddered and tucked her runaway hair behind her ear. “Now that’s a think tank.”

On the left, there are lots of small organizations in Washington that publish granular research on specific economic trends. But the most significant liberal think tank in recent years has been the Center for American Progress, founded in 2003 by the former Bill Clinton chief of staff (and current Hillary Clinton campaign chair) John Podesta as his party’s answer to the conservative Heritage Foundation. CAP has done a lot of innovative policy work, especially on universal preschool and health care, but it was always less of a research organization than a shadow government for an opposition in exile. When Obama was elected, roughly a third of CAP’s staff went into his administration. CAP was founded in an era when few liberals were of the opinion that the system itself was broken: If you just found slightly better Democrats, elected them to office and put smarter policies in their hands, they believed, the country would return to the prosperity of the 1990s. Liberal Washington was not equipped, when the financial crisis broke, to tender a holistic analysis of what was ailing the economy. (Today, CAP’s economic ideas are more in line with those of Roosevelt, and in 2015 it released a report on short-termism that anticipated part of “Rewriting the Rules.”)

In 2009, a political scientist named Andrew Rich, known for writing about the “war of ideas,” was drafted to reinvent the Roosevelt Institute as a place for the radical thinking that postcrisis politics seemed to require. Roosevelt at the time was an ad hoc collection of spare progressive parts, including the upkeep of the F.D.R. Library in Hyde Park, N.Y. Rich believed that if you weren’t in Washington, and you weren’t beholden to the party apparatus, and if you got the right people — people who were too idiosyncratic or rough-hewn for academia, or academics who wanted to be politically relevant but needed help with finding an audience for their work — you could create a new kind of institution on a looser, livelier model.

At that moment of upheaval and administration dithering, financial reform was the new Roosevelt’s obvious first priority. Rich brought on Stiglitz and Mike Konczal, whose pseudonymous financial-crisis blog had a cult following among progressives. In 2010, the organization held a conference that prominently featured Elizabeth Warren, then early in her career as a public figure. While Warren worked on the TARP oversight panel, she needed somewhere to park her aide-de-camp, Dan Geldon, to help draft the details of the Consumer Financial Protection Bureau that was being set up on the basis of her ideas. He served as a fellow, and he and Warren maintain close ties to Roosevelt. Warren insisted I come into her office, though she was late to a vote, so she could tell me how enormously enthusiastic she was about Roosevelt’s work: “It’s a new voice in American political discourse. Their message is, We can do better than this! They’re bringing fundamental optimism back to the center of American life.”

When Wong took over in 2012, she continued to recruit staff members and fellows who were at once nonaligned and well connected: to the A.F.T. and S.E.I.U., Demos, MoveOn, the Clintons. By January 2015, Wong had decided, along with her communications director, Marcus Mrowka, and her vice president of research and policy, Nell Abernathy, to prepare for the coming election by creating a full-dress economic agenda that would be there for the candidates’ taking. “Rewriting the Rules” got funding from the Ford Foundation, whose decision last year to refocus around the issue of inequality was influenced by Roosevelt, and whose president, Darren Walker, effused to me about Wong as an “incandescent leader” for the progressive movement. While written by Stiglitz, the paper was worked out in consultation with labor officials, academics, congressional staff members and — unusually for a think tank — advocates from places like Color of Change, Naral and the Black Civic Engagement Fund.