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.