The Supreme Court’s decision in the 2010 Citizens United case transformed the world of politics. It loosened restrictions on campaign spending and unleashed a flow of anonymous donor money to nonprofit groups run by political activists.

In the months before the ruling dropped in January of that year, a group of conservative activists came together to create just such an organization. Its mission would be to, at the time, block then-President Barack Obama’s pet initiatives.

The activists included Federalist Society leader Leonard Leo and his ideological soulmate, a hard-edged activist named Virginia Thomas, the wife of Supreme Court Justice Clarence Thomas.

“Ginni really wanted to build an organization and be a movement leader,” said a person familiar with her thinking at that time. “Leonard [Leo] was going to be the conduit of that.”

She also had a rich backer: Harlan Crow, the manufacturing billionaire who had helped Thomas and her husband in many ways, from funding luxury vacations to picking up tuition payments for their great-nephew.

At the time, the Citizens United ruling was widely expected, as the court had already signaled its intentions. When it came, it upended nearly 100 years of campaign […]