text:  So the Supreme Court on Friday cut back sharply on the power of federal agencies to interpret the laws that they administer and ruled that courts should rely on their own interpretation of ambiguous laws. The decision will likely have far-reaching effects across the country from environmental regulations to health care costs. So the justices overruled their landmark 1984 decision in Chevron v. Natural Resources Defense Council, which gave rise to the doctrine known as the Chevron Doctrine.