The federal government Friday filed its opening brief to the U.S. Supreme Court in possibly the most consequential administrative law case in decades, imploring the justices not to overturn nearly four decades of “Chevron deference” to government agencies.

“Stare decisis principles weigh heavily in favor of adhering to Chevron, which has been a cornerstone of administrative law reflected in thousands of judicial decisions—and which has provided a stable background rule against which Congress has legislated—for 40 years,” U.S. Solicitor General Elizabeth Prelogar wrote in the brief.