The U.S. Supreme Court on Thursday appointed an O'Melveny & Myers partner to argue an “orphaned” position in the high-stakes dispute over the status of administrative law judges at the U.S. Securities and Exchange Commission.

Anton Metlitsky, a former clerk to Chief Justice John Roberts Jr. who's based in New York, will argue later this year in Lucia v. SEC, an appeal of a 2016 decision by the U.S. Court of Appeals for the D.C. Circuit.

The D.C. Circuit ruled that the administrative judges are SEC employees, not constitutional officers who must be hired by the president, a court or a department head. The commission's longstanding practice was to pick the judges through an internal staff process.

In a separate case the Tenth Circuit ruled that the judges are constitutional officers, setting up a circuit split that made Supreme Court review likely. The high court's decision in the case could affect thousands of proceedings at the SEC and other federal agencies whose administrative judges are appointed in similar fashion.

In November, U.S. Solicitor General Noel Francisco informed the court that the Trump administration would no longer defend the D.C Circuit ruling. The SEC moved immediately to “ratify” the appointments of its five in-house judges in its capacity as a department head.

The high court on Jan. 12 granted certiorari in the Lucia case anyway, even though both sides—the challenger and the government—now agreed that the traditional hiring practice for administrative judges was unconstitutional because the judges exercise “significant authority” and should be viewed as officers.

That oddity occurs rarely at the Supreme Court. But when it does, the justices appoint someone to defend the orphaned lower court ruling that neither of the parties embrace, so that both sides can be fully aired.

By tradition, the justice who oversees the circuit that decided the case below picks one of his or her former law clerks to argue. Roberts oversees the D.C. Circuit, so it is not surprising that one of his clerks was named. Metlitsky did not respond to requests for comment.

Metlitsky, an appellate specialist, has not argued previously before the Supreme Court, but that too conforms to tradition. These appointments have been launching pads for numerous Supreme Court advocates—including Roberts himself, as well as Maureen Mahoney, now a retired partner at Latham & Watkins.

Mark Perry of Gibson, Dunn & Crutcher represents Raymond Lucia, a financial adviser who challenged the status of the SEC judge who barred him from the investment industry because of anti-fraud violations.

In a brief for Lucia, Perry agreed with the government that the issue needed to be resolved and that the high court should appoint someone to defend the D.C. Circuit ruling.

Perry wrote that the division over the status of administrative law judges “has generated substantial confusion and disruption throughout the administrative state.”