A group of watchdog organizations will roll out a new multi-state effort to share information and best practices on campaign finance legislation Thursday, the first step in an effort to force organizations that spend millions on political activity to disclose their donors.

The States’ Unified Network Center will begin as a Web presence to highlight proposed legislation and standing campaign finance law. The group will also organize a database of nonprofit groups that spend money in state elections, in hopes of stitching together the state-by-state patchwork of campaign finance databases.

“This collaboration will enable us to make major inroads in improving the transparency of donors,” said Ann Ravel, chairwoman of the California Fair Political Practices Commission. “Ultimately, the group could go in many other directions, such as joining enforcement matters, potentially joining in some sort of pressure groups of states with the federal government.”

State-run campaign finance groups in 10 states, including New York, California, Alaska, Idaho, Maine, Montana, Maryland, Massachusetts, Washington and Iowa, along with New York City, will form the SUN Center, which begins as an informal working group. Ravel decided to push for a nationwide alliance after an outside group that didn’t have to report its donors spent millions against a tax initiative on the ballot in 2012.

That group, Americans for Responsible Leadership, got the $11 million it spent on the initiative from a series of other so-called dark money organizations — nonprofits operating under sections 501(c)(3), 501(c)(4) and 501(c)(6) of the tax code, all of which are able to undertake different amounts of political spending without filing reports with the Federal Election Commission. ARL’s money came from Americans for Job Security and the Center to Protect Patient Rights, two groups funded through the network operated by the conservative Koch brothers.

Americans for Responsible Leadership didn’t have to disclose its donors after making its first expenditure on the initiative, under a provision of California law known as the first-bite rule. The California state Senate eliminated that rule this year.

The SUN Center will highlight bills aimed at forcing those organizations to file reports disclosing their funding sources when they spend money on state races. Under federal campaign finance law, outside groups must file when they spend money on a federal race, but state laws vary widely.

Ravel said she wanted to form a bipartisan coalition, which meant attracting red states such as Alaska and Idaho along with blue states like Washington and Massachusetts.

“Some are red states, some are blue states. They have all got the same issue and are concerned about the same issue,” she said.

But the coalition will lose its champion in just a few weeks. Ravel and Republican appointee Lee Goodman were confirmed to seats on the Federal Election Commission by a voice vote in the Senate last week. The two will take their seats in late October, Ravel said, adding that she and Goodman seem to see eye to eye on transparency issues.

“Clearly, I’m not going to be able to participate in the task force of states, but I think that transparency and disclosure and getting information to the public is really important,” Ravel said. At her confirmation hearing, she said, Goodman “and I both agreed about that, so hopefully he and I can work together to achieve those goals.”