Professor McGann said such research organizations all shared the problem of maintaining independence from donors. But, he said, Mr. Podesta’s may be less susceptible to conflicts of interest than those financed primarily by a single patron.

Image John D. Podesta founded the Center for American Progress, where he was visited two years ago by his onetime boss. Credit... Doug Mills/The New York Times

“When there is a range of funders,” he said, “even if they are all left of center,” the beneficiary is not “beholden to any one of them or any single group.”

Mr. Podesta did not respond to an interview request made through Ms. Palmieri. But she emphasized that he had set up the Center for American Progress in a way to keep it at arm’s length from its patrons.

“You want to be careful that you are able to maintain autonomy in your work,” she said. “So our donors and our board members don’t direct policy projects or weigh in on our policy positions. And we don’t accept donations for directed work”  that is, work in which donors want their money used to study a specific issue.

After the Clinton administration, Mr. Podesta initially worked as a lobbyist, taking on clients like the Nevada Resort Association and the American Insurance Association. But after the Republican sweep in the 2002 midterm elections, he decided to focus on helping Democrats rebuild.

He observed that a leading source of the Republicans’ success was their superior intellectual infrastructure: institutions outside government that helped develop and communicate pragmatic conservative ideas, even when the party was not in power.

Mr. Podesta focused on building a liberal counterweight to the conservative Heritage Foundation, a well-financed group that has funneled experts into government positions and produces readable policy reports for Congress. That counterweight became the Center for American Progress.