A new effort by Koch Industries and its GOP allies to draw attention to the role of wealthy donors on the left has put a spotlight on Democracy Alliance, an invitation-only group that seeks to organize the giving of liberal political contributors.

Since it launched in 2005, the group’s roughly 100 members have helped create robust infrastructure of think tanks, research organizations and political support groups, helping finance organizations such as Media Matters for America, a media watchdog group; America Votes, which coordinates the efforts of allied interest groups; and Catalist, which provides voter data.

The alliance does not distribute money itself. Rather, it vets organizations seeking funding and recommends certain groups to its members, called “partners,” who are required to donate at least $200,000 a year to endorsed organizations. It does not disclose who participates, but mega-donors such as billionaire hedge fund manager George Soros, venture capitalist Rob McKay, hedge fund manager Tom Steyer and trial lawyers Steve and Amber Mostyn have been identified as members.

Together, such wealthy players have pumped an estimated $500 million into an array of liberal organizations over the last decade.

In taking aim at the organization, Koch allies have seized upon an internal document produced for Democracy Alliance's spring conference in Chicago that was made public. The 60-page portfolio, which was first disclosed by Politico and is being widely circulated in conservative circles, describes the internal strategies about 20 groups on the left that the alliance has recommended for funding this year.

The briefing book also lists a bigger group of roughly 170 organizations, most of which were nominated for support by individual alliance members. That broad list is the basis of a chart being circulated among Republican Hill staffers that depicts Democracy Alliance as the central hub of a vast network.

Gara LaMarche, president of Democracy Alliance, said in an interview that it was not accurate to suggest that alliance members were the financial muscle behind all those organizations.

“We have always focused on a relatively small number of groups that we think are key actors in the progressive infrastructure,” he said. The broader list provided in the document “is our acknowledgment that there are many groups that do good work and that our partners believe are worthy of nomination.”

This spring, alliance partners pledged to give about $30 million to the core 20 groups they support, a slight boost over the amount raised for the same organizations last year.

Three of the main groups the alliance recommends for backing are the American Constitution Society, the Brennan Center for Justice and the Fund for the Republic, which were described in the briefing book as "helping to provide the intellectual and financial firepower needed to reshape our democracy."

Together, Democracy Alliance members provided $5.18 million of the $17.74 million combined budgets of the three organizations in 2013, according to the document.

Michael Waldman, president of the Brennan Center, said the group discloses the "overwhelming number" of its donors in its annual reports and is proud of its support from alliance members.

"Thank goodness these philanthropists are backing efforts to reduce the role of big money and give citizens a bigger voice," he said, echoing comments made by officials from other groups endorsed by the alliance.

LaMarche said that while he was not happy that the group’s private materials were disclosed, the episode reinforced a growing consensus within the Democracy Alliance that it should pull back the curtain on its activities in the coming months.

“The strategies we wish to employ will be very transparent, the groups we wish to invest in will be very transparent,” he said. While some members will want to maintain a low profile, others are willing to be more formally associated with the group, LaMarche added. “There will be significant steps to greater transparency. I think that’s the right thing to do.”

Tom Hamburger contributed to this report.