All of these results are good for the rule of law, for federalism, and therefore for America. Indeed, the decision in Sackett v. EPA continues a renewed commitment to these principles on the Supreme Court's part. Let us hope as bigger cases come down at this term’s end that it is only a precursor to even better victories.

The rule of law presupposes clarity of language. By its own words, law both empowers the government and places limits on that empowerment. Otherwise, we would fall into one of two dystopias: an anarchy from a timid government unsure of its capacities or a tyranny from public officers held to no discernable restraints.

The need for clarity in the law underlay Thursday’s Supreme Court decision in Sackett v. EPA . The decision sought to further define the term “the waters of the United States” in the Clean Water Act of 1972 and thus roll back the Environmental Protection Agency’s regulatory powers.

In the majority opinion, Justice Samuel Alito lauded the success achieved by the Clean Water Act. People can now use many bodies of water that were once unusably polluted. But determining the extent of the above phrase has been a subject of debate between and within both courts and federal agencies for 50 years. Do the waters of the United States only include interstate avenues of commerce? Do they involve any body of water, however small and temporary, down to puddles in a person’s backyard? Judges, bureaucrats, and scholars have put forward arguments bordering on both of these extremes and everywhere in between over the decades.

Alito sought to limit how judges interpreted and enforced the term toward the narrower definition. “[W]aters of the United States” included only what people commonly understood as “streams, oceans, rivers, and lakes” or some body of water permanently connected to the same, he argued.

While the particular definition of this term will not touch most of our lives, the general principle and practice will. For one, Alito’s opinion placed restraints on governmental power over America's citizens. Bureaucrats have tried to read laws such as the Clean Water Act as broadly as possible. Doing so has expanded their regulatory authority over private citizens, businesses, and groups in all kinds of ways. To the extent they did so through the manipulation of the laws, they infringed on our liberty.

Alito affirmed and exercised the principle that bureaucrats cannot define statutory language however they wish, expanding it to meet their goals and preferences. Instead, the government possesses the power to act only so far as the law’s terms dictate. And the laws do possess a clarity of language discernable by judges and others reading them. The laws thereby dictate that government can act only over certain areas in certain ways that other persons can point out and require bureaucrats to obey.

For another, Alito’s opinion struck a blow for federalism. Justice Clarence Thomas’s concurring opinion focused on this issue more than Alito’s, though the two were consistent on this point. Part of the debate over the Clean Water Act is not the power of the government over individual people but the regulatory authority of the national versus the state governments.

Our Founders established a system that divided the exercise of the people’s political power between one national and many state governments. It did so to achieve the same purpose that laws seek. The national government is given control over matters affecting the whole nation, matters it is best suited to address. States receive the rest of legitimate governmental powers, namely those local matters it is most ready to consider. This division also allows the different levels of government to check each other against tyranny, even as each seeks to act more effectively.

Over the last century, the national government has eroded these lines, accruing increasing power once exercised by the states, either directly or through other means. Thomas pointed out how the court’s opinion on Thursday reimposed some of the old limits, even though he would go even further than the majority did. States now will have a greater responsibility to enact proper regulations to protect America’s local waters for the health, safety, and convenience of the people.

Adam Carrington is an associate professor of politics at Hillsdale College.