President Donald Trump’s administration switched sides Wednesday in an important case pending before the Supreme Court concerning a major issue of federal agency law.

The case, Lucia v. SEC, has major implications for the process by which federal agencies try or punish those in violation of laws or regulations, and could retroactively nullify thousands of agency decisions.

At issue in the litigation is an agency’s decision to allow career bureaucrats to preside as the functional equivalent of judges during enforcement proceedings. These officials, called administrative law judges (ALJs), are not appointed by the president, a court, or the head of the agency, but they exercise significant authority on behalf of the U.S. government in official proceedings. ALJs can, among other things, issue subpoenas, make decisions about the credibility of witnesses or the admissibility of evidence, and issues provisional rulings that are generally upheld on final review — if a final review occurs at all.

The Constitution requires that the president, the courts, or the head of an executive department appoint all “inferior officers” of the United States.