By having the case reargued, Roberts put the liberals in a box and transformed the decision’s impact on political campaigns. Illustration by Barry Blitt

When Citizens United v. Federal Election Commission was first argued before the Supreme Court, on March 24, 2009, it seemed like a case of modest importance. The issue before the Justices was a narrow one. The McCain-Feingold campaign-finance law prohibited corporations from running television commercials for or against Presidential candidates for thirty days before primaries. During that period, Citizens United, a nonprofit corporation, had wanted to run a documentary, as a cable video on demand, called “Hillary: The Movie,” which was critical of Hillary Clinton. The F.E.C. had prohibited the broadcast under McCain-Feingold, and Citizens United had challenged the decision. There did not seem to be a lot riding on the outcome. After all, how many nonprofits wanted to run documentaries about Presidential candidates, using relatively obscure technologies, just before elections?

Chief Justice John G. Roberts, Jr., summoned Theodore B. Olson, the lawyer for Citizens United, to the podium. Roberts’s voice bears a flat-vowelled trace of his origins, in Indiana. Unlike his predecessor, William Rehnquist, Roberts rarely shows irritation or frustration on the bench. A well-mannered Midwesterner, he invariably lets one of his colleagues ask the first questions.

That day, it was David Souter, who was just a few weeks away from announcing his departure from the Court. In keeping with his distaste for Washington, Souter seemed almost to cultivate his New Hampshire accent during his two decades on the Court. In response to Souter’s questions, Olson made a key point about how he thought the case should be resolved. In his view, the prohibitions in McCain-Feingold applied only to television commercials, not to ninety-minute documentaries. “This sort of communication was not something that Congress intended to prohibit,” Olson said. This view made the case even more straightforward. Olson’s argument indicated that there was no need for the Court to declare any part of the law unconstitutional, or even to address the First Amendment implications of the case. Olson simply sought a judgment that McCain-Feingold did not apply to documentaries shown through video on demand.

The Justices settled into their usual positions. The diminutive Ruth Bader Ginsburg was barely visible above the bench. Stephen Breyer was twitchy, his expressions changing based on whether or not he agreed with the lawyer’s answers. As ever, Clarence Thomas was silent. (He was in year three of his now six-year streak of not asking questions.)

Then Antonin Scalia spoke up. More than anyone, Scalia was responsible for transforming the dynamics of oral arguments at the Supreme Court. When Scalia became a Justice, in 1986, the Court sessions were often somnolent affairs, but his rapid-fire questioning spurred his colleagues to try to keep pace, and, as Roberts said, in a tribute to Scalia on his twenty-fifth anniversary as a Justice, “the place hasn’t been the same since.” Alternately witty and fierce, Scalia invariably made clear where he stood.

He had long detested campaign-spending restrictions, frequently voting to invalidate such statutes as violations of the First Amendment. For this reason, it seemed, Scalia was disappointed by the limited nature of Olson’s claim.

“So you’re making a statutory argument now?” Scalia said.

“I’m making a—” Olson began.

“You’re saying this isn’t covered by it,” Scalia continued.

That’s right, Olson responded. All he was asking for was a ruling that the law did not prohibit this particular documentary by this nonprofit corporation during those thirty days. If the Justices had resolved the case as Olson had suggested, today Citizens United might well be forgotten—a narrow ruling on a remote aspect of campaign-finance law.

Instead, the oral arguments were about to take the case—and the law—in an entirely new direction.

Supreme Court cases become landmarks in different ways. Lawrence v. Texas, the 2003 gay-rights decision striking down anti-sodomy laws, began with a trivial contretemps in an apartment building just outside Houston. On the other hand, the importance of the constitutional challenge to the Affordable Care Act, the signature domestic achievement of the Obama Presidency, was apparent as soon as it was filed. (A decision is expected in June.) The result in Bush v. Gore was important, but the reasoning turned out to be perishable; the decision has not been cited again by the Justices.

In one sense, the story of the Citizens United case goes back more than a hundred years. It begins in the Gilded Age, when the Supreme Court barred most attempts by the government to ameliorate the harsh effects of market forces. In that era, the Court said, for the first time, that corporations, like people, have constitutional rights. The Progressive Era, which followed, saw the development of activist government and the first major efforts to limit the impact of money in politics. Since then, the sides in the continuing battle have remained more or less the same: progressives (or liberals) vs. conservatives, Democrats vs. Republicans, regulators vs. libertarians. One side has favored government rules to limit the influence of the moneyed in political campaigns; the other has supported a freer market, allowing individuals and corporations to contribute as they see fit. Citizens United marked another round in this contest.

In a different way, though, Citizens United is a distinctive product of the Roberts Court. The decision followed a lengthy and bitter behind-the-scenes struggle among the Justices that produced both secret unpublished opinions and a rare reargument of a case. The case, too, reflects the aggressive conservative judicial activism of the Roberts Court. It was once liberals who were associated with using the courts to overturn the work of the democratically elected branches of government, but the current Court has matched contempt for Congress with a disdain for many of the Court’s own precedents. When the Court announced its final ruling on Citizens United, on January 21, 2010, the vote was five to four and the majority opinion was written by Anthony Kennedy. Above all, though, the result represented a triumph for Chief Justice Roberts. Even without writing the opinion, Roberts, more than anyone, shaped what the Court did. As American politics assumes its new form in the post-Citizens United era, the credit or the blame goes mostly to him.

Floyd Brown had worked around the fringes of the conservative movement for years before he became famous, in 1988. He was the political director of an independent campaign committee called Americans for Bush, which produced and broadcast a commercial featuring Willie Horton, a convicted murderer who received a weekend furlough in Massachusetts and then committed several grisly crimes. When the election was over, Americans for Bush had outlived its usefulness. So Brown embraced the notoriety that came with the co–authorship of the Willie Horton ad, and founded a new organization. He called it Citizens United.

Brown acquired a sidekick, a recent dropout from the University of Maryland named David Bossie. Bossie also had a passion for conservative politics and, like Brown, an entrepreneurial bent. In 1992, Brown appointed Bossie his “chief researcher,” and they narrowed their focus to publicizing harsh critiques of the personal and financial affairs of Bill and Hillary Clinton. Eight years later, with the inauguration of George W. Bush, the public profile of Citizens United receded. Bossie, who had become president of the group in 2000, thought that it needed a niche to distinguish it from the other conservative organizations in Washington. Bossie’s revelation came in 2004, when he first saw advertisements for Michael Moore’s movie “Fahrenheit 9/11.” Bossie recognized that the documentary was doing a kind of double duty. “Fahrenheit 9/11” and the television commercials promoting it were at once political salvos against the reëlection of President Bush and a potential source of profit.