A lingering lawsuit forcing the disclosure of donors behind a 2012 attack ad against U.S. Sen. Sherrod Brown has just pushed an entire category of dark-money political donors into the light.

The new standard for donor disclosure is the result of a deadline that passed this week. The U.S. Supreme Court choose not to take up a case originally filed the last time Brown was up for re-election. Citizens for Responsibility and Ethics in Washington (CREW), which filed the suit, argued that a negative TV ad smearing Brown could not hide its donors behind a decades-old Federal Elections Commission rule.

A lower court agreed. And because the nation’s top jurists won’t hear the case, good government and public watchdog groups say secretive groups airing mostly attack ads across America this fall must start outing their donors in the next week.

“This is a great day for transparency and democracy,” CREW Executive Director Noah Bookbinder said in a statement reported by the Washington Post. “We’re about to know a lot more about who is funding our elections.”

Opponents of the move say any forced disclosure would scare off donors and chill free speech.

While some advocates for transparency celebrate the legal decision as a victory, others worry that 501(c)(4) organizations, also called social welfare groups, will simply morph into super PACs, which are still protected from disclosing their donors under previous high court rulings like the landmark 2010 Citizens United decision.

Already some of the biggest names that bankroll political messaging have shifted to the super PAC model. The Koch brothers, two wealthy conservatives, have formed Americans for Prosperity Action ahead of the midterm elections to operate alongside Americans For Prosperity (AFP), which pumped millions into Ohio to help Republican Sen. Rob Portman handily dispatch a 2016 challenge from former Gov. Ted Strickland. While AFP is a 501(c)(4) social welfare group no longer shielded from the FEC rule, its super Pac, a 527 organization named for the IRS code section under which it is formed, is not required to disclose its donors, who can give limitless amounts.

Eye on Ohio, an investigative group of journalists focused on good government and transparency, reports that 12 such 501(c)(4) organizations are active in the current midterm races. With activity spanning the nation, some have spent exclusively on Ohio races.

In all, the groups have spent $17.5 million nationally and $889,899 in Ohio, according to research provided by Eye on Ohio Executive Director Lucia Walinchus. The dozen organizations include liberal causes like gun reform and access to abortion. But while left-leaning groups like Everytown for Gun Safety Action Fund and Planned Parenthood Action Fund are giving about $10,000 each, these secretive groups are flooding the airwaves to support conservative issues and Republican candidates.

Leading the spending among social welfare organizations active in Ohio are the U.S. Chamber of Commerce and Coalition for Growth & Opportunity. The tax exempt groups are barred by IRS rules from spending more than half their annual giving on political activities. The U.S. Chamber of Commerce has injected $600,000 while Coalition for Growth and Opportunity has spent $102,835 already on Ohio races.

According to the Center for Responsive Politics, a nonpartisan political ad and spending tracker, both groups supported Republicans and attacked Democrats in 2016. Coalition for Growth and Opportunity received $1 million in two donations this election cycle from Generation Now INC, a Columbus-based group that says it supports energy independence and nuclear power. The Beacon Journal has received no response after asking about the group's donors — information that could soon be public knowledge.

Reach Doug Livingston at 330-996-3792 or dlivingston@thebeaconjournal.com.