The U.S. Supreme Court is considering whether to limit the power of administrative agencies. Kisor v. Wilkie, which was argued last month, is a head-on challenge to the deference afforded to an agency when interpreting its own regulations. The Supreme Court prescribed this level of deference in 1997. In Auer v. Robbins, a unanimous decision written by the late Justice Antonin Scalia, the court held that an agency’s interpretation of its own regulations should control if its interpretation is not plainly erroneous or inconsistent with the regulations. Now, just 22 years later, the court seems willing to reconsider this decision.

The challenge comes from petitioner James Kisor, a Vietnam veteran who suffers from post-traumatic stress disorder. In 1982, the Department of Veteran Affairs denied Kisor’s request for benefits. He applied again in 2006—this time, armed with additional documentation in support of his diagnosis that was previously unavailable to him. The VA granted this second application but only prospectively; the decision would not apply retroactively to 1982. The VA’s explanation was that the documents were not “relevant” to his prior request. Using Auer deference, the VA was able to interpret and define relevant, and then it was Kisor who bore the burden of establishing that the VA’s interpretation was not valid.