 The Supreme Court took a big hit to the power of federal agencies across the U.S. government. They overturned a bedrock of administrative law known as Chevron deference. This is a Supreme Court precedent that had been on the books for 40 years. It hit its 40th birthday this week. But now the Supreme Court is saying it will not reach 41, overturning this. So what does this mean? This precedent had given federal agencies authority to regulate in areas where Congress has written laws that are ambiguous.