The Supreme Court’s ruling earlier this spring in McCutcheon v F.E.C., which increased the amount of money donors can contribute to political campaigns for federal office, has added new fuel to an 80-year-old debate between those who contend that the Supreme Court decides cases on the basis of abstract principles of law and those who argue that judicial rulings are based primarily on political and economic considerations.

Liberal critics of the Roberts court now draw a comparison between the court’s rulings in campaign finance cases like McCutcheon and Citizens United v F.E.C. (2010), both of which expand the ability of the rich to contribute to candidates, and decisions in two recent voting rights cases, Crawford v. Marion County Election Board (2008), which imposed onerous voter-identification requirements, and last year’s Shelby County v. Holder, which overturned Department of Justice preclearance requirements in Southern states. Both of these decisions restrict the political influence of the poor and of minorities.

The debate over the ideological motivations of the judiciary has a long history. In the 20th century, this debate placed on one side, in the words of the former Yale law professor Grant Gilmore, those who believed that “the law was a symmetrical structure of logical propositions, all neatly dovetailed. The truth or error, the rightness or wrongness, of a judicial decision could be determined by merely checking to see whether it fitted into the symmetrical structure.” On the other side were those who believed that the “rules of law do not so much explain as conceal the bases of judicial decision. A judge’s holding in a case is an ad hoc response to a unique state of facts, rationalized, after the event, with a dissimulation more or less conscious, and fitted willy-nilly into the Procrustean bed of approved doctrine. The motivations of the judicial response are buried, obscure, unconscious and — even to the judge — unknowable.”

This dispute flared in more contemporary terms last year with the publication of “How Business Fares in the Supreme Court,” an article in The Minnesota Law Review, which concluded that “the Roberts Court is much friendlier to business than either the Burger or Rehnquist Courts.” The argument gained credibility in part because one of its authors, Richard Posner, is a widely respected conservative jurist, appointed to the Seventh Circuit of the United States Court of Appeals by Ronald Reagan.