JUSTICE BLACKMUN delivered the opinion of the Court.

In this litigation, we granted certiorari before judgment in the United States Court of Appeals for the Eighth Circuit in order to consider the constitutionality of the Sentencing Guidelines promulgated by the United States Sentencing Commission. The Commission is a body created under the Sentencing Reform Act of 1984. The United States District Court for the Western District of Missouri ruled that the Guidelines were constitutional. United States v. Johnson, 682 F. Supp. 1033 (1988).
 

Background

Both indeterminate sentencing and parole were based on concepts of the offender's possible, indeed probable, rehabilitation, a view that it was realistic to attempt to rehabilitate the inmate and thereby to minimize the risk that he would resume criminal activity upon his return to society. It obviously required the judge and the parole officer to make their respective sentencing and release decisions upon their own assessments of the offender's amenability to rehabilitation. As a result, the court and the officer were in positions to exercise, and usually did exercise, very broad discretion....

Historically, federal sentencing - the function of determining the scope and extent of punishment - never has been thought to be assigned by the Constitution to the exclusive jurisdiction of any one of the three Branches of Government. Congress, of course, has the power to fix the sentence for a federal crime, and the scope of judicial discretion with respect to a sentence is subject to congressional control. Congress early abandoned fixed-sentence rigidity, however, and put in place a system of ranges within which the sentencer could choose the precise punishment. Congress delegated almost unfettered discretion to the sentencing judge to determine what the sentence should be within the customarily wide range so selected....Thus, under the indeterminate-sentence system, Congress defined the maximum, the judge imposed a sentence within the statutory range (which he usually could replace with probation), and the Executive Branch's parole official eventually determined the actual duration of imprisonment....

Serious disparities in sentences, however, were common. Rehabilitation as a sound penological theory came to be questioned and, in any event, was regarded by some as an unattainable goal for most cases.... Fundamental and widespread dissatisfaction with the uncertainties and the disparities continued to be expressed. Congress had wrestled with the problem for more than a decade when, in 1984, it enacted the sweeping reforms that are at issue here.

Helpful in our consideration and analysis of the statute is the Senate Report on the 1984 legislation. The Report referred to the "outmoded rehabilitation model" for federal criminal sentencing, and recognized that the efforts of the criminal justice system to achieve rehabilitation of offenders had failed. It observed that the indeterminate-sentencing system had two "unjustifi[ed]" and "shameful" consequences. The first was the great variation among sentences imposed by different judges upon similarly situated offenders. The second was the uncertainty as to the time the offender would spend in prison. Each was a serious impediment to an evenhanded and effective operation of the criminal justice system....
 

The Act

1. It rejects imprisonment as a means of promoting rehabilitation, and it states that punishment should serve retributive, educational, deterrent, and incapacitative goals.

2. It consolidates the power that had been exercised by the sentencing judge and the Parole Commission to decide what punishment an offender should suffer. This is done by creating the United States Sentencing Commission, directing that Commission to devise guidelines to be used for sentencing, and prospectively abolishing the Parole Commission.

3. It makes all sentences basically determinate. A prisoner is to be released at the completion of his sentence reduced only by any credit earned by good behavior while in custody.

4. It makes the Sentencing Commission's guidelines binding on the courts, although it preserves for the judge the discretion to depart from the guideline applicable to a particular case if the judge finds an aggravating or mitigating factor present that the Commission did not adequately consider when formulating guidelines. The Act also requires the court to state its reasons for the sentence imposed and to give "the specific reason" for imposing a sentence different from that described in the guideline.

5. It authorizes limited appellate review of the sentence. It permits a defendant to appeal a sentence that is above the defined range, and it permits the Government to appeal a sentence that is below that range. It also permits either side to appeal an incorrect application of the guideline.

Thus, guidelines were meant to establish a range of determinate sentences for categories of offenses and defendants according to various specified factors, "among others." The maximum of the range ordinarily may not exceed the minimum by more than the greater of 25% or six months, and each sentence is to be within the limit provided by existing law.
 

The Sentencing Commission

The Responsibilities of the Commission

This Litigation

Petitioner had pleaded guilty to the first count of his indictment (conspiracy and agreement to distribute cocaine). The Government thereupon moved to dismiss the remaining counts. That motion was granted.  Petitioner was sentenced under the Guidelines to 18 months' imprisonment, to be followed by a 3-year term of supervised release.

Petitioner filed a notice of appeal to the Eighth Circuit, but both petitioner and the United States, pursuant to this Court's Rule 18, petitioned for certiorari before judgment. Because of the "imperative public importance" of the issue, as prescribed by the Rule, and because of the disarray among the Federal District Courts, we granted those petitions.
 

Delegation of Power

The nondelegation doctrine is rooted in the principle of separation of powers that underlies our tripartite system of Government. The Constitution provides that "[a]ll legislative Powers herein granted shall be vested in a Congress of the United States," U.S. Const., Art. I, 1, and we long have insisted that "the integrity and maintenance of the system of government ordained by the Constitution" mandate that Congress generally cannot delegate its legislative power to another Branch.  We also have recognized, however, that the separation-of-powers principle, and the nondelegation doctrine in particular, do not prevent Congress from obtaining the assistance of its coordinate Branches. In a passage now enshrined in our jurisprudence, Chief Justice Taft, writing for the Court, explained our approach to such cooperative ventures: "In determining what [Congress] may do in seeking assistance from another branch, the extent and character of that assistance must be fixed according to common sense and the inherent necessities of the government co-ordination." So long as Congress "shall lay down by legislative act an intelligible principle to which the person or body authorized to [exercise the delegated authority] is directed to conform, such legislative action is not a forbidden delegation of legislative power."

Applying this "intelligible principle" test to congressional delegations, 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. Accordingly, this Court has deemed it "constitutionally sufficient if Congress clearly delineates the general policy, the public agency which is to apply it, and the boundaries of this delegated authority."

Until 1935, this Court never struck down a challenged statute on delegation grounds. After invalidating in 1935 two statutes as excessive delegations, see A. L. A. Schechter Poultry Corp. v. United States, and Panama Refining Co. v. Ryan, we have upheld, again without deviation, Congress' ability to delegate power under broad standards.

In light of our approval of these broad delegations, we harbor no doubt that Congress' delegation of authority to the Sentencing Commission is sufficiently specific and detailed to meet constitutional requirements. Congress charged the Commission with three goals: to "assure the meeting of the purposes of sentencing as set forth" in the Act; to "provide certainty and fairness in meeting the purposes of sentencing, avoiding unwarranted sentencing disparities among defendants with similar records . . . while maintaining sufficient flexibility to permit individualized sentences," where appropriate; and to "reflect, to the extent practicable, advancement in knowledge of human behavior as it relates to the criminal justice process." Congress further specified four "purposes" of sentencing that the Commission must pursue in carrying out its mandate: "to reflect the seriousness of the offense, to promote respect for the law, and to provide just punishment for the offense"; "to afford adequate deterrence to criminal conduct"; "to protect the public from further crimes of the defendant"; and "to provide the defendant with needed . . . correctional treatment...."

Developing proportionate penalties for hundreds of different crimes by a virtually limitless array of offenders is precisely the sort of intricate, labor-intensive task for which delegation to an expert body is especially appropriate. Although Congress has delegated significant discretion to the Commission to draw judgments from its analysis of existing sentencing practice and alternative sentencing models, "Congress is not confined to that method of executing its policy which involves the least possible delegation of discretion to administrative officers."  We have no doubt that in the hands of the Commission "the criteria which Congress has supplied are wholly adequate for carrying out the general policy and purpose" of the Act.
 

Separation of Powers

Mistretta... argues that Congress, in constituting the Commission as it did, effected an unconstitutional accumulation of power within the Judicial Branch while at the same time undermining the Judiciary's independence and integrity. Specifically, petitioner claims that in delegating to an independent agency within the Judicial Branch the power to promulgate sentencing guidelines, Congress unconstitutionally has required the Branch, and individual Article III judges, to exercise not only their judicial authority, but legislative authority - the making of sentencing policy - as well. Such rulemaking authority, petitioner contends, may be exercised by Congress, or delegated by Congress to the Executive, but may not be delegated to or exercised by the Judiciary.

At the same time, petitioner asserts, Congress unconstitutionally eroded the integrity and independence of the Judiciary by requiring Article III judges to sit on the Commission, by requiring that those judges share their rulemaking authority with nonjudges, and by subjecting the Commission's members to appointment and removal by the President. According to petitioner, Congress, consistent with the separation of powers, may not upset the balance among the Branches by co-opting federal judges into the quintessentially political work of establishing sentencing guidelines, by subjecting those judges to the political whims of the Chief Executive, and by forcing judges to share their power with nonjudges.
 

Location of the Commission

According to express provision of Article III, the judicial power of the United States is limited to "Cases" and "Controversies."  In implementing this limited grant of power, we have refused to issue advisory opinions or to resolve disputes that are not justiciable.  These doctrines help to ensure the independence of the Judicial Branch by precluding debilitating entanglements between the Judiciary and the two political Branches, and prevent the Judiciary from encroaching into areas reserved for the other Branches by extending judicial power to matters beyond those disputes "traditionally thought to be capable of resolution through the judicial process." As a general principle, we stated as recently as last Term that "`executive or administrative duties of a nonjudicial nature may not be imposed on judges holding office under Art. III of the Constitution.'"

Nonetheless, we have recognized significant exceptions to this general rule and have approved the assumption of some nonadjudicatory activities by the Judicial Branch. In keeping with Justice Jackson's Youngstown admonition that the separation of powers contemplates the integration of dispersed powers into a workable Government, we have recognized the constitutionality of a "twilight area" in which the activities of the separate Branches merge....

That judicial rulemaking, at least with respect to some subjects, falls within this twilight area is no longer an issue for dispute. None of our cases indicate that rulemaking per se is a function that may not be performed by an entity within the Judicial Branch, either because rulemaking is inherently nonjudicial or because it is a function exclusively committed to the Executive Branch. On the contrary, we specifically  have held that Congress, in some circumstances, may confer rulemaking authority on the Judicial Branch.  Pursuant to this power to delegate rulemaking authority to the Judicial Branch, Congress expressly has authorized this Court to establish rules for the conduct of its own business and to prescribe rules of procedure for lower federal courts in bankruptcy cases, in other civil cases, and in criminal cases, and to revise the Federal Rules of Evidence....

In light of this precedent and practice, we can discern no separation-of-powers impediment to the placement of the Sentencing Commission within the Judicial Branch....

Given the consistent responsibility of federal judges to pronounce sentence within the statutory range established by Congress, we find that the role of the Commission in promulgating guidelines for the exercise of that judicial function bears considerable similarity to the role of this Court in establishing rules of procedure under the various enabling Acts. Such guidelines, like the Federal Rules of Criminal and Civil Procedure, are court rules - rules, to paraphrase Chief Justice Marshall's language in Wayman, for carrying into execution judgments that the Judiciary has the power to pronounce....
 

Composition of the Commission

The text of the Constitution contains no prohibition against the service of active federal judges on independent commissions such as that established by the Act....

Our inferential reading that the Constitution does not prohibit Article III judges from undertaking extrajudicial duties finds support in the historical practice of the Founders after ratification. Our early history indicates that the Framers themselves did not read the Constitution as forbidding extrajudicial service by federal judges. The first Chief Justice, John Jay, served simultaneously as Chief Justice and as Ambassador to England, where he negotiated the treaty that bears his name. Oliver Ellsworth served simultaneously as Chief Justice and as Minister to France. While he was Chief Justice, John Marshall served briefly as Secretary of State and was a member of the Sinking Fund Commission with responsibility for refunding the Revolutionary War debt.

All these appointments were made by the President with the "Advice and Consent" of the Senate. Thus, at a minimum, both the Executive and Legislative Branches acquiesced in the assumption of extrajudicial duties by judges....

Subsequent history, moreover, reveals a frequent and continuing, albeit controversial, practice of extrajudicial service. In 1877, five Justices served on the Election Commission that resolved the hotly contested Presidential election of 1876, where Samuel J. Tilden and Rutherford B. Hayes were the contenders. Justices Nelson, Fuller, Brewer, Hughes, Day, Roberts, and Van Devanter served on various arbitral commissions. Justice Roberts was a member of the commission organized to investigate the attack on Pearl Harbor. Justice Jackson was one of the prosecutors at the Nuremberg trials; and Chief Justice Warren presided over the commission investigating the assassination of President Kennedy....

In light of the foregoing history and precedent, we conclude that the principle of separation of powers does not absolutely prohibit Article III judges from serving on commissions such as that created by the Act. The judges serve on the Sentencing Commission not pursuant to their status and authority as Article III judges, but solely because of their appointment by the President as the Act directs. Such power as these judges wield as Commissioners is not judicial power; it is administrative power derived from the enabling legislation. Just as the nonjudicial members of the Commission act as administrators, bringing their experience and wisdom to bear on the problems of sentencing disparity, so too the judges, uniquely qualified on the subject of sentencing, assume a wholly administrative role upon entering into the deliberations of the Commission. In other words, the Constitution, at least as a per se matter, does not forbid judges to wear two hats; it merely forbids them to wear both hats at the same time....

We are somewhat more troubled by petitioner's argument that the Judiciary's entanglement in the political work of the Commission undermines public confidence in the disinterestedness of the Judicial Branch. While the problem of individual bias is usually cured through recusal, no such mechanism can overcome the appearance of institutional partiality that may arise from judiciary involvement in the making of policy. The legitimacy of the Judicial Branch ultimately depends on its reputation for impartiality and nonpartisanship. That reputation may not be borrowed by the political Branches to cloak their work in the neutral colors of judicial action.

Although it is a judgment that is not without difficulty, we conclude that the participation of federal judges on the Sentencing Commission does not threaten, either in fact or in appearance, the impartiality of the Judicial Branch. We are drawn to this conclusion by one paramount consideration: that the Sentencing Commission is devoted exclusively to the development of rules to rationalize a process that has been and will continue to be performed exclusively by the Judicial Branch....

JUSTICE SCALIA, dissenting.

While the products of the Sentencing Commission's labors have been given the modest name "Guidelines," they have the force and effect of laws, prescribing the sentences criminal defendants are to receive. A judge who disregards them will be reversed. I dissent from today's decision because I can find no place within our constitutional system for an agency created by Congress to exercise no governmental power other than the making of laws.

It should be apparent from the above that the decisions made by the Commission are far from technical, but are heavily laden (or ought to be) with value judgments and policy assessments. This fact is sharply reflected in the Commission's product, as described by the dissenting Commissioner:

"Under the guidelines, the judge could give the same sentence for abusive sexual contact that puts the child in fear as for unlawfully entering or remaining in the United States. Similarly, the guidelines permit equivalent sentences for the following pairs of offenses: drug trafficking and a violation of the Wild Free-Roaming Horses and Burros Act; arson with a destructive device and failure to surrender a cancelled naturalization certificate; operation of a common carrier under the influence of drugs that causes injury and alteration of one motor vehicle identification number; illegal trafficking in explosives and trespass; interference with a flight attendant and unlawful conduct relating to contraband cigarettes; aggravated assault and smuggling $11,000 worth of fish."

The lawmaking function of the Sentencing Commission is completely divorced from any responsibility for execution of the law or adjudication of private rights under the law. It is divorced from responsibility for execution of the law not only because the Commission is not said to be "located in the Executive Branch" (as I shall discuss presently, I doubt whether Congress can "locate" an entity within one Branch or another for constitutional purposes by merely saying so); but, more importantly, because the Commission neither exercises any executive power on its own, nor is subject to the control of the President who does.... And the Commission's lawmaking is completely divorced from the exercise of judicial powers since, not being a court, it has no judicial powers itself, nor is it subject to the control of any other body with judicial powers. The power to make law at issue here, in other words, is not ancillary but quite naked. The situation is no different in principle from what would exist if Congress gave the same power of writing sentencing laws to a congressional agency such as the General Accounting Office, or to members of its staff.

The delegation of lawmaking authority to the Commission is, in short, unsupported by any legitimating theory to explain why it is not a delegation of legislative power. To disregard structural legitimacy is wrong in itself - but since structure has purpose, the disregard also has adverse practical consequences. In this case, as suggested earlier, the consequence is to facilitate and encourage judicially uncontrollable delegation....

By reason of today's decision, I anticipate that Congress will find delegation of its lawmaking powers much more attractive in the future. If rulemaking can be entirely unrelated to the exercise of judicial or executive powers, I foresee all manner of "expert" bodies, insulated from the political process, to which Congress will delegate various portions of its lawmaking responsibility. How tempting to create an expert Medical Commission (mostly M.D.'s, with perhaps a few Ph.D.'s in moral philosophy) to dispose of such thorny, "no-win" political issues as the withholding of life-support systems in federally funded hospitals, or the use of fetal tissue for research. This is an undemocratic precedent that we set - not because of the scope of the delegated power, but because its recipient is not one of the three Branches of Government. The only governmental power the Commission possesses is the power to make law; and it is not the Congress.

It would seem logical to decide the question of which Branch an agency belongs to on the basis of who controls its actions: If Congress, the Legislative Branch; if the President, the Executive Branch; if the courts (or perhaps the judges), the Judicial Branch....

Today's decision may aptly be described as the Humphrey's Executor of the Judicial Branch, and I think we will live to regret it. Henceforth there may be agencies "within the Judicial Branch" (whatever that means), exercising governmental powers, that are neither courts nor controlled by courts, nor even controlled by judges. If an "independent agency" such as this can be given the power to fix sentences previously exercised by district courts, I must assume that a similar agency can be given the powers to adopt rules of procedure and rules of evidence previously exercised by this Court. The bases for distinction would be thin indeed.

Today's decision follows the regrettable tendency of our recent separation-of-powers jurisprudence to treat the Constitution as though it were no more than a generalized prescription that the functions of the Branches should not be commingled too much - how much is too much to be determined, case-by-case, by this Court. The Constitution is not that. Rather, as its name suggests, it is a prescribed structure, a framework, for the conduct of government. In designing that structure, the Framers themselves considered how much commingling was, in the generality of things, acceptable, and set forth their conclusions in the document....

I think the Court errs, in other words, not so much because it mistakes the degree of commingling, but because it fails to recognize that this case is not about commingling, but about the creation of a new Branch altogether, a sort of junior-varsity Congress. It may well be that in some circumstances such a Branch would be desirable; perhaps the agency before us here will prove to be so. But there are many desirable dispositions that do not accord with the constitutional structure we live under. And in the long run the improvisation of a constitutional structure on the basis of currently perceived utility will be disastrous.

I respectfully dissent from the Court's decision.