Obamacare isn’t the only target of conservative judges.

For the past few months, the legal discussion in Washington has centered around the Supreme Court’s upcoming ruling on health care reform. Far less attention has been paid to a decision issued by the U.S. Court of Appeals for the D.C. Circuit on April 13—even though it may prove, in the long run, to be similarly significant.

At first glance, the case, Hettinga v. United States, doesn’t seem to merit much attention, since it concerns a less-than-scintillating subject: the production and distribution of milk. The challengers, Hein and Ellen Hettinga, who own two large milk production and handling companies, were seeking to overturn a federal mandate based on the Agricultural Marketing Agreement Act of 1937. This mandate requires large milk producers and distributors to contribute to a common fund so that the small operators get the same price for their milk. (The mandate could arguably be viewed as one of the last vestiges of centralized, New Deal–style price controls.) Not surprisingly, in a short, unsigned opinion, the D.C. Circuit upheld the mandate, citing a 1993 Supreme Court opinion saying that laws involving economic policy deserve “a strong presumption of validity.”

But one of the D.C. Circuit’s judges, Janice Rogers Brown, issued a remarkable opinion in the case, making clear that she vehemently disagreed with the majority’s presumptions. The opinion was notable not only for its anti-statist editorializing, but also because it suggests that the Affordable Care Act will be far from the last federal regulation to be threatened by conservative judicial activism.

IN 2005, IN AN ARTICLE for The New York Times Magazine, I described a nascent movement of pro-business and libertarian federal judges and think tank activists who hoped to resurrect what one judge called “the Constitution in Exile.” The term referred to a series of legal doctrines that have been dormant since the New Deal but which judges could use to dismantle the post–New Deal regulatory state, including economic regulations, health and safety laws, and environmental laws.

Janice Rogers Brown has long been sympathetic to these goals. A daughter of sharecroppers, she denounced the New Deal in a series of speeches before her confirmation to the D.C. Circuit in 2005. She called 1937—the year the Supreme Court began to uphold the New Deal—“the triumph of our own socialist revolution.” In the same speech, she argued that “protection of property was a major casualty of the revolution of 1937.” During her first years on the federal bench, however, Brown was mostly quiet about her anti-regulatory views.