In the Supreme Court this week, Elena Kagan, the new solicitor general, eloquently defended the long-standing ban on corporate spending in political campaigns. But the conservative justices who spoke showed a disdain for both Congress’s laws and for the court’s own prior rulings. If the ban is struck down, as we fear, elections could be swamped by special-interest money. ...

What the conservatives seemed most concerned about was protecting the interests of corporations. The chief justice and Justice Scalia seemed especially perturbed that what they see as the inviolable right of these legal constructs to speak might be infringed upon.

The more liberal justices including Justice Sonia Sotomayor, who was participating in her first argument were far more sympathetic to the ban on corporate expenditures, but they have only four votes.

There is still some hope that Chief Justice Roberts may decide his affection for corporations is less important than the reputation of the Roberts court. If he does, there is a chance for a limited, and relatively undamaging, ruling that hews closely to the facts of this case.

The underlying dispute is a narrow First Amendment challenge brought by Citizens United, a nonprofit group that wanted to show an anti-Hillary Clinton movie on a video-on-demand service during the primary season. The court could uphold its right to show the movie without opening the door to a new era of political corruption.