In Anchoring the Clean Water Act: Congress's Constitutional Sources of Power to Protect the Nation's Waters, Jay E. Austin and D. Bruce Myers, Jr., Senior Attorneys at the Environmental Law Institute, examine the constitutionality of the Clean Water Act. As Austin and Myers explain, Supreme Court rulings have left serious questions about the breadth of the Clean Water Act’s coverage, prompting Congress to consider legislation (such as the Clean Water Restoration Act of 2007) to clarify the Clean Water Act’s intended scope. Such legislation, of course, raises questions about the bounds and sources of Congress’s power to protect the nation’s waters. In this issue brief, the authors identify the constitutional powers Congress can draw upon to protect waters nationwide. Austin and Myers explain how the Commerce Clause and the treaty power, as well as the unenumerated powers of the Necessary and Proper Clause, combine to give Congress broad constitutional authority to regulate the nation’s waters in a comprehensive fashion. In addition, Austin and Myers describe how these broad constitutional powers are supplemented by less discussed sources of powers, such as the Property Clause and the spending power.