As we reported back in
March 2019, the Supreme Court of the United States was
reexamining what level of deference, if any, courts must show to a
federal agency in cases challenging an agency's interpretation
of its own regulations. Today, in Kisor v. Wilkie, No. 18-15, a narrow
majority of the Supreme Court relied on principles of stare
decisis in refusing to overrule the Court's past rulings
addressing the deference question. After doing so, however, the
majority purported to "reinforce [the] limits" of the
test courts must apply when evaluating an agency's
interpretation of its own regulations.
Much ink will be spilled over Kisor given the issues
involved and the intensity of the disagreeing views expressed by
four Justices. For now, let us focus on what constitutes the
opinion of the Court that lower federal courts must follow on a
going-forward basis. (The opinion of the Court was authored by
Justice Kagan and joined by Chief Justice Roberts and
