You could make a good case that the last ten years have been relatively good for liberals. Democrats won two out of three presidential elections and controlled Congress for four years, two of them overlapping with the Obama presidency. It was a too-brief window, but during that time they managed to accomplish an awful lot—passing major of the financial sector, ending the war in Iraq, launching a major regulatory effort to tame climate change, formally allowing gays into the military, and finally passing something that looks like universal health care.

There have been setbacks and disappointments too. Democrats never restored tax levels to what they were during the Clinton era, recent fiscal deals have choked some vital domestic programs, and the economic recovery has been fitful. Meanwhile, a generation of conservative judges have handed more power to states, which in some parts of the country has given the right new license on abortion rights and other issues. But thanks to favorable demographic changes, Democrats seem in strong position to protect what they’ve accomplished nationally and maybe, sometime soon, move on to new projects—whether it’s redoubling efforts on climate change, doing something about work-family issues, various political reforms, or aggressively attacking inequality.

Liberals are in this position for a whole bunch of reasons. One of them is an organization that, on Thursday, will celebrate its tenth anniversary. I’m talking about the Center for American Progress, and its affiliated political arm, the Center for American Progress Action Fund. Like most people who work in or around politics and identify with the center-left, I’m hardly a disinterested observer. I am broadly sympathetic to the organization’s political outlook, know many people there personally, and have participated in their events. But I think most people in Washington would agree that CAP plays a vital role in the liberal ecosystem—doing a job that, ten years ago, nobody else was doing.

The right has long had a set of institutions that serve a similar role. The best known of these is the Heritage Foundation, which after its establishment in 1973 helped craft the conservative policy revolution that started with the election Ronald Reagan and crested, finally, during the presidency of George W. Bush. Heritage served multiple roles during that span—as an incubator of ideas, a supplier of arguments, and a source of talent. The brains and money behind Heritage saw the think-tank as an antidote to the prevailing liberal consensus in Washington, as put forth by places like the Brookings Institution (and academia generally) and reinforced by the New York Times (and rest of the media establishment). But there was a certain irony in this mandate: Whatever the ideological sympathies of these supposedly liberal institutions, or the people within them, they were not avowedly political organizations. On the contrary, they strove to maintain—and, I would argue, succeeded in maintaining—a strict posture of non-partisanship and even non-ideology. Other think-tanks and organizations had more clearly progressive outlooks, but even they tended to be heavily analytical and/or narrowly focused. They did invaluable work. (The Economic Policy Institute's annual State of Working America may be the single most important non-government report on inequality.) But one niche remained unfilled.

On the left, the only true analogue to a group like Heritage—a group with a broad issue portfolio, determined to blend policy and politics—was the Democratic Leadership Council and its affiliated think-tank, the Progressive Policy Institute. It had considerable influence on the Democratic Party, particularly during the 1990s, when Bill Clinton—an early DLC member—became president. But DLC/PPI was all about pulling Democrats, and public policy in general, to the right. By the late 1990s, liberals were anxious to pull the party and the conversation back to the left. That was the idea behind CAP, as it founder, longtime Clinton adviser John Podesta, explained at the time. “One of the things that The Heritage Foundation, I think, has done a good job of is that they've gotten their people out into that public debate,” Podesta told National Public Radio in 2003. “They've had a strategy to not just come up with analysis, not just to write good ideas in papers and in academic journals but to actually get out and fight for the hearts and minds of the American people for public opinion. And that's what we aim to do.”