Dark money's front man: Eric O'Keefe works behind the scenes to help the Koch brothers sway elections.

• Author: Murphy, Bruce
• Position: Charles G. Koch and David H. Koch

On November 2013, a little-known conservative activist named Eric O'Keefe brazenly disobeyed a court order and leaked information to The Wall Street Journal editorial page about a secret "John Doe" investigation involving campaign finance violations by political operatives surrounding Wisconsin Governor Scott Walker. O'Keefe's group, the conservative Wisconsin Club for Growth, was among the parties being investigated.

It was the beginning of an extraordinary scorched-earth campaign by O'Keefe to harass and undermine the John Doe investigators, who had targeted alleged illegal coordination between Walker and conservative groups including Club for Growth and Wisconsin Manufacturers and Commerce. But O'Keefe had a bigger goal in mind: overturning decades of established law in America saying that independent advocacy groups could not coordinate with political campaigns.

O'Keefe launched a series of suits against the prosecutors leading the investigation, continued to leak information about the probe, and publicly denounced it as a "partisan" attack on free speech. He went on conservative talk radio to accuse prosecutors of imposing "a traumatic, unconstitutional abuse on people" and compared those being investigated to "a rape victim"--adding, "I am saying this deliberately."

Together with his lawyer, David Rivkin, O'Keefe pushed the idea that the John Doe investigators conducted early morning "paramilitary raids" violating the constitutional rights of those being investigated, and which resulted in stories in conservative publications like National Review. Stories of these abuses were discredited by an audiotape in which investigators treated their alleged victim politely. Yet a majority of the Wisconsin Supreme Court in July released an extraordinary ruling that shut down the John Doe probe, with three of the four-member majority citing unproven violations of constitutional rights.

The Club for Growth and Wisconsin Manufacturers and Commerce had together provided more than $8 million supporting these four justices in their last elections, accounting for anywhere from 48 percent to 76 percent of the total spent on each justice's behalf. The justices returned the favor, writing a decision that seemed to ignore Wisconsin law and decades of U.S. Supreme Court decisions holding that independent advocacy groups cannot coordinate with political campaigns, since that would make them no longer independent.

It was a huge victory for O'Keefe and for Walker, one that has legalized the unlimited use of dark money in campaigns in Wisconsin and could influence how such cases are handled in other jurisdictions. Long after the end of Walker's 2016 Republican presidential campaign, O'Keefe's national aspirations still have legs.

"Wisconsin has sort of become ground zero for the testing of how far outside groups could coordinate with candidates," says Tara Malloy, senior counsel for the Campaign Legal Center, a nonprofit advocacy group that has closely followed the Wisconsin fight. But she notes that what is happening here is part of a much larger conservative agenda. Across the country, Malloy says, "The envelope is being pushed on coordination in all areas."

All of which has made O'Keefe a public figure, despite a long history of quietly effective conservative advocacy. He has been dubbed the "third Koch brother" for his efforts to lead and recruit donors to numerous advocacy groups connected to billionaire industrialists David and Charles Koch.

O'Keefe founded the Sam...