Reducing rampant pollution across the United States was so important that when Congress passed many environmental protection laws, including the Clean Air Act, Clean Water Act, and Safe Drinking Water Act, it didn’t want to leave enforcement only to the executive branch.

Congress specifically wrote into those laws ways for citizens to enforce them through the courts when the government does not act to address the problem. Called “citizen suit provisions,” those parts of the laws allow regular people and advocacy groups to sue companies they believe are violating the law. Citizens can also sue federal agencies that fail to enforce the laws.

Since the 1970s, those provisions have been used in over 2,000 lawsuits. In fact, a majority of environmental cases are citizen suit cases. Citizen suits have been used to halt the construction of dams to protect endangered species, end the injection of wastewater into groundwater, and secure US$14.2 million in civil penalties for illegal emissions from a petrochemical facility. In short, these cases have shaped modern environmental law.

Now, in a legal filing, the Trump administration is saying citizens should not be allowed to enforce environmental laws. Rather, despite what the laws say, the US Department of Justice has claimed in a case involving Elon Musk’s xAI that people should be required to leave enforcement to the executive branch—even if the executive decides to take no action.

A history of success

For more than 50 years, citizen suits have been an effective part of cleaning up the environment in the US The process is fairly straightforward: A person or group must send a formal notification to the person, company or agency they suspect of violating the law—with a copy to the US Environmental Protection Agency. If after 60 days the problem is not rectified, the people can sue.

Citizen suits often ask the courts to order a stop to the polluting activity, payments for reducing or cleaning up the harm done, and civil penalties paid to the government. But if the government has already begun an enforcement action or is actively prosecuting the violator, a citizen suit cannot proceed.