Prior to the New Deal, the American judiciary was highly suspicious of regulatory legislation, which was viewed as upsetting the common law's support for private property interests and freedom of contract. Laissez-faire policies reigned. Regulatory statutes were vulnerable to invalidation under a variety of constitutional theories, including substantive due process, federalism and, for a brief period of time, delegating legislative authority to the executive branch, a constitutional offense under separation-of-powers principles.

Since the advent of the modern administrative state and the Administrative Procedure Act (APA) of 1946,¹ the "nondelegation" doctrine has been, for all practical purposes, a dead letter in the federal arena. Even the most broad-sweeping authorizations have barely been questioned. Instead, the delegation of complex regulatory details to executive agencies is generally recognized as promoting efficient and effective government. So long as Congress provides some "intelligible principles" to guide the agency in its implementation of a statute, delegations have not raised constitutional concerns.² Courts simply review agency interpretations of open-ended delegations as a matter of administrative law under the familiar standard from Chevron, U.S.A., Inc. v. Natural Resources Defense Council, Inc.,³ upholding the regulation so long as the agency's construction is reasonable.⁴