After the U.S. Supreme Court overturned Chevron deference Friday, some lawyers expect legal fights to emerge in lower courts over the ability to challenge prior federal agency rules that relied on the long-standing doctrine.

In Loper Bright Enterprises v. Raimondo, the justices overturned the landmark 1984 decision that established the principle that courts should defer to an agency’s reasonable interpretation of an ambiguous statute. Judges have upheld thousands of agency actions under the 40-year-old Chevron deference doctrine, which gave agencies staffed with experts wide power to interpret laws when regulating the environment, health and a vast array of other policy areas.