The Supreme Court’s conservative supermajority spent several hours Wednesday attacking a longstanding legal doctrine that gives federal agencies wide latitude to create policies and regulations in various areas of life.

The justices heard two cases concerning the so-called Chevron deference, which emerged from a 1984 case. Oral arguments in the first case went well beyond the allotted hour, with the conservatives signaling their willingness to overturn the decades-old case and their liberal colleagues sounding the alarm on how such a reversal would upend how the federal government enforces all kinds of regulations.

Congress routinely writes open-ended, ambiguous laws that leave the policy details to agency officials. The Chevron deference stipulates that when disputes arise over regulation of an ambiguous law, judges should defer to agency interpretations, as long as the interpretations are reasonable.

…

The three liberal justices warned during Wednesday’s pair of arguments that overturning the 1984 decision in Chevron would force courts to make policy decisions that they argue are better left for experts employed by federal agencies.

“I see Chevron as doing the very important work of helping courts stay away from policymaking,” Justice Ketanji Brown Jackson said, adding later: “I’m worried about the courts becoming über legislators.”