Much of the greatness of the United States Constitution can be attributed to the elegant pen of Gouverneur Morris, who, as leader of the Committee on Style, fashioned the text into a coherent and practical symmetry. Because of his writing, the document’s first three articles lay out the structure of the separation of powers, each dealing with the powers of the legislature, the executive, and the judiciary respectively.

The economical wording of the Legislative Vesting Clause performs three critical constitutional functions. First, it defines the Congress as “a Senate and House of Representatives.” Thus, when the Constitution elsewhere refers to “Congress,” as it frequently does, it refers to a specifically defined institution consisting of two subsidiary houses or “branches.” In establishing two legislative chambers, the House and the Senate, the Framers paid heed to a requirement championed by the respected voice of Baron de Montesquieu, who opined that liberty could be preserved only if two branches of the legislature, chosen from different constituencies, could check each other. Similarly, in his influential Thoughts on Government (1776), John Adams declared that “[a] single assembly is liable to all the vices, follies, and frailties of an individual.”

The clause thus reflects a particular suspicion of what James Madison called the “impetuous vortex” of the federal legislative power. As Alexander Hamilton explained in The Federalist No. 22, unlike the Congress under the Articles of Confederation, the Congress under the Constitution would have such greater powers that it was necessary that it be divided for the sake of the people’s safety. In The Federalist No. 62, Madison agreed, stating that having a Senate “doubles the security to the people by requiring the concurrence of two distinct bodies in schemes of usurpation or perfidy, where the ambition or corruption of one, would otherwise be sufficient.”

Thus, no bill can become a law without the assent of both branches of Congress, which respond to different constituencies. In sum, the Legislative Vesting Clause represents a kind of separation of power of the legislative houses within a larger separation of powers among the legislative, executive, and judicial institutions.

Second, and more substantively, the trio of clauses that begin each of the first three Articles of the Constitution—the Legislative Vesting Clause, the Executive Vesting Clause (Article II, Section 1, Clause 1), and the Judicial Vesting Clause (Article III, Section 1)—allocates classes of governmental power to different, and differently selected and responsive, federal actors. The “executive Power” is vested in the President, the “judicial Power” is vested in the life tenured federal courts, and “[a]ll legislative Powers herein granted” are vested in Congress. By vesting different classes of power in different institutions, the Constitution clearly contemplates that there are types of governmental powers that, as Madison put it in The Federalist No. 48, “may in their nature be legislative, executive, or judiciary.” This is not to say, however, that one can neatly and easily place every particular exercise of governmental power into a legislative, executive, or judicial category. Indeed, Madison, in The Federalist No. 37, wrote that “[e]xperience has instructed us that no skill in the science of government has yet been able to discriminate and define, with sufficient certainty, its three great provinces—the legislative, executive, and judiciary. . . . Questions daily occur in the course of practice . . . which puzzle the greatest adepts in political science.” Moreover, according to Madison, some overlap is necessary to make the separation of powers work. The “partial agency” of one branch in the workings of the others was essential. The Federalist No. 47.

Third, all legislative powers that are granted are vested in Congress, but Congress is not vested with all legislative powers. Rather, the Constitution vests in Congress only those particular legislative powers “herein granted” and directs us to the other provisions in the Constitution to determine the precise content of the federal legislative power. The Legislative Vesting Clause thus does not itself serve as a font of powers, but rather functions as a designation of who must exercise the legislative powers granted elsewhere in the Constitution. Once a particular substantive power is properly labeled legislative (for example, the power over interstate commerce), then the Legislative Vesting Clause makes clear that it is Congress that is to exercise that particular power.

The Constitution, however, does not directly circumscribe the line that separates legislative from executive or judicial power. If a law is so precise and unambiguous that it leaves nothing to the discretion of executive or judicial actors, then enforcement by the executive and application by the judiciary are mechanical tasks, and no one could complain that executive or judicial actors are somehow exercising legislative power vested exclusively in Congress. But few laws are or can be crafted so precisely. It is commonplace for executive and judicial actors to need to interpret enacted laws in the course of their duties. Indeed, some measure of discretion in the interpretation and application of laws is the essence of the executive and judicial powers. But can the formal exercise of executive or judicial interpretation ever become so extensive in shaping the meaning of a law that the executive or judicial actor in reality becomes the lawmaker?

The scheme of American constitutional government requires answers to the question where the legislative power ends and the executive and judicial powers begin, but those answers have been, and remain, notoriously elusive. For example, is it possible for Congress to enact a law so vague that, in substance, it impermissibly allows executive or judicial actors to usurp the legislative function that is vested exclusively in Congress? Or is the only purely “legislative” power vested in Congress simply the power to enact a law through the processes required by Article I, Section 7, so that all acts of interpretation, even “interpretation” of an utterly vacuous enactment, is a permissible exercise of executive or judicial power so long as it is performed by an executive or judicial actor? These are chief among those questions that “puzzle the greatest adepts in political science”— both in the eighteenth century and today.

There are some contexts in which the Constitution specifically enumerates a congressional power to designate subsidiary lawmakers. The Territories and Property Clauses (Article IV, Section 3, Clause 2), which gives Congress power to make “all needful Rules and Regulations respecting the Territory or other Property belonging to the United States,” has long been construed to give Congress general governmental power over federal possessions, including the power to create territorial legislatures with independent law-making authority, and the same reasoning might allow Congress to designate executive officers as the effective authorities over federal property. Similarly, the Enclave Clause (Article I, Section 8, Clause 17) has long been understood to grant equivalent power with respect to the District of Columbia. Outside of those contexts that specifically authorize delegation of legislative authority to non-congressional lawmakers, however, the question whether law interpretation can ever impermissibly morph into law making looms large.

The Supreme Court’s first major encounter with this question, which is often described as the question of legislative delegation, remains among its most instructive. Wayman v. Southard (1825) involved a challenge, as an impermissible delegation of legislative power, to a congressional statute authorizing federal courts to make changes to the rules for such matters as serving process and executing judgments. Congress’s enumerated legislative power, under the Necessary and Proper Clause, surely allows it to make laws “for carrying into Execution” the judicial power by specifying forms of process and the manner of execution of judgments. In a lengthy dictum, Chief Justice John Marshall, for a unanimous Court, noted that “[i]t will not be contended that Congress can delegate to the Courts, or to any other tribunals, powers which are strictly and exclusively legislative.” But, as the Chief Justice also noted, some powers are not, in their nature, exclusively legislative. The fact that Congress could properly legislate in the area of judicial procedure did not mean that the courts could not exercise it as well. This point is crucial to an understanding of the Constitution’s essential structure and to the lines drawn by the document among the various governmental powers.

The Constitution divides and allocates governmental powers, not governmental functions or actions. There may be some actions—such as the passage of a bill, the direction of troops in battle, or the entry of a criminal judgment—that are uniquely the exercise of legislative, executive, or judicial powers, respectively. But other actions can easily fall within scope of more than one of the three vested constitutional powers. For example, Congress has the power of establishing in law the right of persons to present claims against the government. But it can vest the action of adjudicating those claims in the courts (as part of its judicial power of deciding cases), or in the executive branch (as part of its power to execute the laws faithfully), or in itself as part of its own legislative power by passing private bills for the relief of individuals. Thus, in terms of the actions that fall within them, the legislative, executive, and judicial powers are thus partially overlapping rather than mutually exclusive categories.

Chief Justice Marshall’s point was that so long as the action in question falls within the power vested in the actor who performs it, it is constitutional even if could also have been performed by some other actor under that actor’s vested power. Thus, reasoned the Court in Wayman, if the courts could promulgate rules of procedure under their “judicial Power,” it would not constitute a delegation of legislative power for Congress to channel that power through a statute, even if the statute provided no clear guidelines. Because this discussion was dictum, it was not necessary for the Court to determine precisely which procedural rules had to be fixed by Congress and which could be set by courts under a vague authorization from Congress; as Marshall noted, “there is some difficulty in discerning the exact limits within which the legislature may avail itself of the agency of its Courts” in such matters. Similarly difficulty arises when Congress seeks to “avail itself” of the aid of the executive in implementing statutes, perhaps by having agencies pass regulations or conduct adjudications to fill out the meaning of a statute, as when the First Congress provided for the payment of military pensions “under such regulations as the President of the United States may direct” and required licensed Indian traders to be governed “by such rules and regulations as the President shall prescribe.” Marshall explained that “[t]he difference between the departments undoubtedly is, that the legislature makes, the executive executes, and the judiciary construes the law; but the maker of the law may commit something to the discretion of the other departments, and the precise boundary of this power is a subject of delicate and difficult inquiry. . . .”

As for how to resolve this “delicate and difficult inquiry” when necessary, Marshall wrote: “The line has not been exactly drawn which separates those important subjects, which must be entirely regulated by the legislature itself, from those of less interest, in which a general provision may be made, and power given to those who are to act under such general provisions, to fill up the details.” Moreover, the line may well need to be drawn in different places depending upon the subject matter of the legislation; more vagueness, for example, may be permissible when Congress grants authority to the President in military or foreign affairs than in other areas.

Courts and scholars have spent two centuries trying to improve upon, or avoid, Chief Justice Marshall’s distinction between “important” matters and matters of “less interest” as the touchstone for determining the kind and quality of discretion that Congress can permissibly vest in executive or judicial actors without crossing the line into a delegation of legislative authority. It is unclear whether there has been improvement. The more common solution has been avoidance.

Until the New Deal, there were many cases raising challenges to statutes as delegations of legislative authority. In all of those cases the Court treated the challenges as constitutionally serious, but in only two did it find a statute unconstitutional. Most of those cases involved so called “conditional legislation,” in which the effective date or precise terms of a statute depended upon factual or policy determinations by executive actors, such as making tariffs or tariff rates dependent upon findings by the President about the activities of other countries. For example, in J. W. Hampton, Jr.Co. v. United States (1928), the Court upheld a statute authorizing the President to adjust tariff rates to “equalize the . . . costs of production” in the United States and the exporting country. In oft-quoted language, the Court set out what remains the governing standard, noting that a statute vesting even very broad discretion in executive or judicial actors is constitutional if “Congress shall lay down by legislative act an intelligible principle to which the person or body . . . is directed to conform.” The Court found the principle of equalizing costs of production to be intelligible, and its application therefore an exercise of executive rather than legislative power, because such an allocation of responsibility between the President and Congress was consistent with “common sense and the inherent necessities of . . . governmental coordination.”

Seven years later, in Panama Refining Co. v. Ryan (1935) and A.L.A. Schechter Poultry Corp. v. United States (1935), the Court found an absence of “intelligible principle[s]” in two provisions of the National Industrial Recovery Act, and for the first and only times in the nation’s history found statutes to be unconstitutional delegations of legislative authority. The sheer scope of power over national affairs granted by the statute was unprecedented, and many scholars have speculated that this feature of the statute played a role in the decisions.

Since 1935, the Court has never invalidated a statute on delegation grounds. A possible exception is Clinton v. New York (1998), which held that when Congress gave the President a limited line-item veto power, it violated the Presentment Clause (Article I, Section 7, Clause 2). While the majority opinion did not expressly rely upon delegation concerns, those issues were extensively briefed, were invoked by three dissenting Justices who thought the statute easily constitutional on delegation grounds, and may have shaped somewhat the majority’s Presentment Clause holding. But in all other assertions of an unconstitutional delegation of legislative power, the Court has found validating “intelligible principle[s]” in statutes requiring agencies to determine “excessive profits,” to grant licenses as “public interest, convenience, or necessity” require, to set “fair” and “equitable” prices, and to prohibit corporate structures that “‘unfairly or inequitably’ distribute voting power among security holders.” In Mistretta v. United States (1989), the Court all but declared the delegation doctrine nonjusticiable (that is, a dispute incapable of being resolved by the courts), when it upheld an open-ended grant of authority to the United States Sentencing Commission to set ranges for criminal sentences by explaining that “our jurisprudence has been driven by a practical understanding that in our increasingly complex society, replete with ever changing and more technical problems, Congress simply cannot do its job absent an ability to delegate power under broad general directives.” Justice Antonin Scalia dissented on grounds narrowly tailored to the specific powers conferred upon the Sentencing Commission, but he agreed with the otherwise unanimous majority’s view that courts should not generally try to place enforceable limits on the kind and quality of discretion that Congress grants to other actors.

Indeed, in 2001, Justice Scalia authored a unanimous opinion in Whitman v. American Trucking Ass’ns, Inc., which upheld, with relatively little discussion, a statute instructing the Environmental Protection Agency to set an ambient air quality standard “which in the judgment of the Administrator . . . is requisite to protect the public health” with “an adequate margin of safety.” Justice Clarence Thomas indicated a willingness to reconsider the Court’s lax delegation doctrine in an appropriate case, but no other cur rent Justice has echoed those sentiments. Indeed, the votes on the merits in delegation cases in the Supreme Court from 1989 to 2012 were 53–0 against the challenges.

Notwithstanding the strong signals from the Supreme Court that delegation challenges will not be well received, lower courts judges continue to find delegation problems with statutes at a rate that some might find surprising given the seeming clarity of the doctrine. Some Justices, on hard-to-predict occasions, invoke delegation concerns as a reason to construe statutes in order to avoid having those statutes raise constitutional issues, as did a plurality of the Court in Industrial Union Dep’t, AFL-CIO v. American Petroleum Inst. (1980). Justices Scalia and Ruth Bader Ginsburg, neither of whom is noted for sympathy for delegation challenges, employed delegation concerns in this fashion in their dissent from the majority in Reynolds v. United States (2012).

The consequences of the Court’s reluctance to police the boundaries of the legislative, executive, and judicial powers cannot be overstated. In modern times, Congress routinely enacts statutes that place the vast bulk of responsibility for promulgating binding norms in administrative agencies (and derivatively in courts that review the decisions of administrative agencies), to the point that agencies are, by any relevant measure, far more important instruments of governance than is Congress.

When he was an academic in 1980, then Professor Scalia urged courts to reinvigorate the delegation doctrine. As a Justice, he abandoned that position because, as he explained in his dissenting opinion in Mistretta, “while the doctrine of unconstitutional delegation is unquestionably a fundamental element of our constitutional system, it is not an element readily enforceable by the courts. Once it is conceded, as it must be, that no statute can be entirely precise, and that some judgments, even some judgments involving policy considerations, must be left to the officers executing the law and to the judges applying it, the debate over unconstitutional delegation becomes a debate not over a point of principle but over a question of degree.” Those who wish for the Court to take delegation concerns more seriously thus need to convince at least some Justices that a test for drawing the line among legislative, executive, and judicial powers can be found that is no more troubling than other tests employed by the Court in other contexts. A return to the first principles articulated by Chief Justice Marshall in Wayman v. Southard might be a productive place to start.