
428 Mich. 314 (1987)
409 N.W.2d 202
KENT COUNTY PROSECUTOR
v.
KENT COUNTY SHERIFF
Docket No. 74055, (Calendar No. 1).
Supreme Court of Michigan.
Argued January 13, 1987.
Decided July 1, 1987.
David H. Sawyer, Prosecuting Attorney, and Timothy K. McMorrow, Chief Appellate Attorney, for the plaintiff.
Varnum, Riddering, Schmidt & Howlett (by Jon F. DeWitt and Jonathan W. Anderson) for defendant Kent County Sheriff.
Richard E. Hillary, Director, and Michael P. Mathews for intervening defendant Kent County Office of the Defender.
Amicus Curiae:
John D. O'Hair, Prosecuting Attorney, and George E. Ward, Chief Assistant Prosecuting Attorney, for the Wayne County Prosecutor.
*317 ON REHEARING
CAVANAGH, J.
I. INTRODUCTION
When we originally considered this case, the Court was divided equally on the constitutionality of the county jail overcrowding act, 1982 PA 325, MCL 801.51 et seq.; MSA 28.1748(1) et seq.[1] Rehearing was granted to resolve the Court's division on this important public issue. We conclude that the act does not infringe upon the Governor's power of executive clemency, and we reverse the Court of Appeals determination of unconstitutionality.
The jail overcrowding act directs a county sheriff to declare a jail overcrowding state of emergency when the general prisoner population of a county jail exceeds one hundred percent of the rated design capacity of the jail.[2] Upon a declaration of emergency, the sheriff is directed to notify designated county executive and judicial officers of the *318 emergency[3] and is exhorted to reduce the prison population by existing legal means such as pretrial diversion, reduction in the bonds of prisoners, and use of day parole.[4] If these steps do not reduce the jail population sufficiently to eliminate jail overcrowding, the sheriff is directed to supply the chief circuit judge of the county with the name of each prisoner, along with details of the prisoner's sentence and the offense for which he was convicted.[5] The chief judge is directed to classify the prisoners into two categories, those whose release would present a high risk to the public safety, and those whose release would not present such a risk. The sheriff is then directed to reduce the sentences of the low-risk prisoners by an equal percentage, set by the chief circuit judge, until the overcrowding is alleviated.
Of course, a statute is presumed constitutional, and a party attacking the constitutionality of an act must overcome this presumption.[6] The Kent County Prosecutor maintains that the jail overcrowding act contravenes Const 1963, art 5, § 14, which gives the Governor the power to grant reprieves, commutations, and pardons after conviction of an offense.
We can summarize our disagreement as follows: The overcrowded conditions of many Michigan jails are legitimate legislative concerns. In enacting the jail overcrowding act, the Legislature has taken an appropriate measure to address this problem, while intruding upon the Governor's powers as little as possible. The incidental benefit that accrues to the prisoners released under the *319 act does not amount to an unconstitutional invasion of the powers of the executive branch.
II. THE PURPOSE OF THE ACT
In assessing the validity of a statute against a constitutional challenge, an appropriate starting point is the legislative purpose in enacting the statute. In equal protection challenges, for example, a showing of discriminatory intent has long been required in those cases which allege racial discrimination. Rogers v Lodge, 458 US 613, 617; 102 S Ct 3272; 73 L Ed 2d 1012 (1982), reh den 459 US 899 (1982). In Mobile v Bolden, 446 US 55; 100 S Ct 1490; 64 L Ed 2d 47 (1980), it was held that an electoral scheme for selecting city councilmen at-large was not unconstitutional per se even though the effect of the scheme was to deprive minority voters of the opportunity to elect any of their members to the council. If the purpose of the at-large scheme, however, was to diminish the voting potential of minorities, then the statute would have been unconstitutional.
It is also appropriate to examine the legislative purpose in considering other constitutional challenges. For example, in Pension Benefit Guaranty Corp v Gray & Co, 467 US 717; 104 S Ct 2709; 81 L Ed 2d 601 (1984), a due process challenge to the provisions of ERISA was made on the ground that they applied retroactively for a period of five months preceding enactment of the statute. In rejecting the challenge, the Court explained:
The retroactive aspects of legislation, as well as the prospective aspects, must meet the test of due process, and the justifications for the latter may not suffice for the former. But that burden is met simply by showing that the retroactive application of the legislation is itself justified by a rational *320 legislative purpose. [467 US 730. Citations and interior quotation marks omitted.]
Turning to the present case, the purpose of the jail overcrowding act is clear. Its entire thrust is to reduce or eliminate the evils fostered by overcrowded jails.[7]
The title of the act provides:

AN ACT to authorize county sheriffs to declare a county jail overcrowding state of emergency; to prescribe the powers and duties of certain judges, county sheriffs, and other county officials; and to provide remedies for a county jail overcrowding state of emergency. [Emphasis added.]
In evaluating the legislative goals behind the jail overcrowding act, it is helpful to keep in mind the Legislature's plenary power over matters dealing with public health and welfare:

*321 The public health and general welfare of the people of the state are hereby declared to be matters of primary public concern. The legislature shall pass suitable laws for the protection and promotion of the public health. [Const 1963, art 4, § 51.]
The overcrowding of jails and prisons and the problems generated by such overcrowding are issues with which the Legislature has traditionally dealt pursuant to the above constitutional mandate. Appellees do not contend that the purpose of the present statute is beyond legislative power. Rather, appellees argue that regardless of purpose, it is the effect of the act which must be considered and that the effect is to grant commutations of sentences.
III. THE EFFECT OF THE ACT
A lawful purpose alone will not save a statute which clearly violates constitutional principles. If the effect of the jail overcrowding act is to violate a constitutional command, then no laudable legislative purpose can save the enactment. However, it is not necessarily fatal to this legislation that, when considered in a vacuum, it appears to interfere with the Governor's executive powers. In State, County & Municipal Workers v Dearborn, 311 Mich 674, 677; 19 NW2d 140 (1945), we explained this point, quoting from Story, Constitutional Law (4th ed), p 380:
"When we speak of a separation of the three great departments of government, and maintain that that separation is indispensable to public liberty, we are to understand this maxim in a limited sense. It is not meant to affirm that they must be kept wholly and entirely separate and *322 distinct, and have no common link or dependence, the one upon the other, in the slightest degree. The true meaning is that the whole power of one of these departments should not be exercised by the same hands which possess the whole power of either of the other departments; and that such exercise of the whole would subvert the principles of a free Constitution."
The United States Supreme Court, while interpreting the federal constitution, also offers persuasive authority. In United States v Nixon, 418 US 683, 707; 94 S Ct 3090; 41 L Ed 2d 1039 (1974), the Court emphasized:
In designing the structure of our Government and dividing and allocating the sovereign power among three co-equal branches, the Framers of the Constitution sought to provide a comprehensive system, but the separate powers were not intended to operate with absolute independence.
Later, in Nixon v Administrator of General Services, 433 US 425, 443; 97 S Ct 2777; 53 L Ed 2d 867 (1977), the United States Supreme Court reasoned:
Like the District Court, we therefore find that appellant's argument rests upon an "archaic view of the separation of powers as requiring three airtight departments of government." Rather, in determining whether the Act disrupts the proper balance between the coordinate branches, the proper inquiry focuses on the extent to which it prevents the Executive Branch from accomplishing its constitutionally assigned functions. Only where the potential for disruption is present must we then determine whether that impact is justified by an overriding need to promote objectives within the constitutional authority of Congress. [Citations omitted; emphasis added.]
*323 The Michigan constitutional provision which appellees contend is violated states:
The governor shall have power to grant reprieves, commutations and pardons after convictions for all offenses, except cases of impeachment, upon such conditions and limitations as he may direct, subject to procedures and regulations prescribed by law. He shall inform the legislature annually of each reprieve, commutation and pardon granted, stating reasons therefor. [Const 1963, art 5, § 14.]
We disagree with the appellees' assertion that the jail overcrowding act permits commutations in violation of this provision.[8]
In our original Kent Co opinion, Justice LEVIN demonstrated why a generalized reduction in sentence in response to a jail emergency did not invade the Governor's power of commutation. See parts IV and V of his opinion. 425 Mich 733-742. Several factors which support his analysis warrant emphasis.
Commutations are acts of individualized clemency, typically motivated by the prisoner's personal characteristics and behavior in jail or prison. In contrast, the sentence reductions under the act are prompted by generalized conditions of the jail *324 or jails within the county, not by the unique characteristics of the affected prisoners. Section 5 of the act, redundantly perhaps, exhorts the sheriff and county judicial and executive officers to utilize existing means, "within the scope of their individual and collective legal authority," to reduce the jail population. Only when those measures are insufficient to eliminate the overcrowding emergency do the substantive provisions of the jail overcrowding act come into play.
Appellees argue that the provision for determining high-risk and low-risk prisoners, § 6 of the act, makes each release turn on individualized prisoner consideration, which is equivalent to a commutation. This is not so. Once the jail emergency is declared, it is the extent of the emergency, and not the characteristics of the prisoners, which determines the number of prisoners who will have their sentences reduced.
Further, the goals of commutations and the jail overcrowding act differ. Commutations are directly aimed at benefiting the released prisoner, and no others. Acts of clemency exist solely for this purpose. Reduction in sentences due to jail overcrowding is directly aimed at alleviating that emergency situation. The released prisoners are not the only ones affected by sentence reductions. The persons still confined enjoy improved living conditions. Undoubtedly, the released prisoners benefit more than those in jail because, by falling into the low-risk category, their sentences are reduced. That benefit, however, is simply an incidental and inevitable result of the final measures taken to alleviate the jail emergency.
IV. AUTHORITY OF THE LEGISLATURE
As shown, the jail overcrowding act's purpose *325 and effect withstands scrutiny. In addition, there are other bases on which to rest the act's validity.
In Oakland Co Prosecutor v Dep't of Corrections, 411 Mich 183; 305 NW2d 515 (1981), the Prison Overcrowding Emergency Powers Act, MCL 800.71; MSA 28.1437(1), endured a constitutional attack similar to the present one. We upheld the constitutionality of that act because it was within the terms of the constitutional grant of power to the Legislature over indeterminate sentences:
The legislature may provide for indeterminate sentences as punishment for crime and for the detention and release of persons imprisoned or detained under such sentences. [Const 1963, art 4, § 45.]
Appellees urge that Oakland Co can be distinguished from the present case because the jail overcrowding act affects determinate, rather than indeterminate, sentences, and the Legislature does not have a constitutional grant of authority over the former as it does over the latter. To require a finding of a constitutional grant of authority to alter determinate sentences, however, it is first necessary to establish that the act actually infringes on the Governor's commutation power. We have found no such violation.
Moreover, in deciding Oakland Co, this Court properly adopted the most narrow holding in deciding the constitutional issues before it.[9] We rested our finding of that act's constitutionality solely on the Legislature's power over indeterminate sentences, thus "the question of its infringement on the Governor's commutation power [was] obviated...." 411 Mich 194. Justice LEVIN continued *326 this narrow analytical approach by holding that jail sentences are indeterminate, at least since the enactment of the jail overcrowding act in 1983. See part III of his opinion. 425 Mich 731-733. Now that the validity of the act is once again before us, we choose to address a broader issue: whether the Legislature, in confronting the present situation affecting the common good, can incidentally reduce jail sentences, whether indeterminate or not.
We find that it can. First, the act ensures enforcement of the regulations governing maintenance of jails, which the Department of Corrections, Bureau of Correctional Facilities, implemented pursuant to legislative directive. MCL 791.262; MSA 28.2322.[10] A jail which is so overcrowded that it triggers the release of prisoners under the act would otherwise be contravening the regulations' minimum-space requirements.[11] Certainly, the Legislature can take measures to enforce these rules promulgated under its authority.
Second, the Legislature has an interest in helping the state and its employees avoid liability when possible. As will be further discussed, past experience has shown that conditions arising from jail and prison overcrowding can lead to suits against jail and prison officials brought by prisoners under 42 USC 1983 for violation of their civil rights.[12] Also, the county where the jail is located *327 could possibly face liability under the public building exception to governmental immunity. MCL 691.1406; MSA 3.996(106).[13] The act provides a method by which the county and its jail officials can alleviate overcrowding before incidents giving rise to potential liability occur.
Finally, the lawfulness of the jail overcrowding act clearly emerges when we consider the constitutional ban of cruel and unusual punishment.[14] While overcrowding of closely held human beings does not necessarily amount to cruel and unusual punishment, the attendant problems, such as understaffing and lack of sanitation, eating, and recreation facilities, frequently do. Such conditions have caused jails and prisons in this state and throughout the United States to be placed under court supervision to implement the ban against cruel and unusual punishment.[15]
*328 No one now doubts the authority of courts to order the release of prisoners confined under conditions violating their Eighth and Fourteenth Amendment rights. It is far too late in the day to argue that such releases are a judicial intrusion on the executive's power of clemency. Similarly, the Legislature, through the jail overcrowding act, is seeking to prevent violations of prisoners' Eighth and Fourteenth Amendment rights. When we consider that many of the prisoners in county jails have yet to be convicted, the state must be especially solicitous of their rights while they are still protected by the presumption of innocence. The act provides bright-line guidance to the courts and sheriff when the likelihood of Eighth and Fourteenth Amendment violations becomes imminent.
Whether the jail overcrowding act may trigger the release of prisoners before conditions become so severe as to violate the cruel and unusual punishment provisions, we need not decide. A threatened injury is enough to justify action. Judgment reversed.
RILEY, C.J., and LEVIN, ARCHER, and GRIFFIN, JJ., concurred with CAVANAGH, J.
BOYLE, J.
I concur in the result of the majority because, upon consideration of the new arguments presented since this Court's original determination *329 in this case, I am now convinced that the grant of power to the Legislature permitting indeterminate sentences allows the reductions called for in the jail overcrowding act.
LEVIN and BRICKLEY, JJ., concurred with BOYLE, J.
GRIFFIN, J.
I concur in the Court's holding that the Legislature is constitutionally empowered to enact the statute in question. To so hold is not to say, however, that it represents the best public policy.
This lawsuit deals with possible encroachment upon the executive's authority. But continued use of early release as a substitute for jail and prison construction could also affect the judicial function. In determining the appropriate sentence to be imposed upon one convicted of crime, a trial judge should be concerned with considerations other than the likelihood that the sentence, once imposed, will later be reduced arbitrarily through the operation of a statute such as this.
Of course, concerns about the wisdom of pursuing such a policy are appropriately addressed to the Legislature.
NOTES
[1]  Our original opinion is found at 425 Mich 718; 391 NW2d 341 (1986). In it, Justice LEVIN set forth the facts which gave rise to this litigation:

The Sheriff of Kent County declared an "overcrowded state of emergency" for the Kent County jail, pursuant to Act 325, on May 12, 1983.
The prosecuting attorney for Kent County commenced this action, seeking a declarative judgment that Act 325 was unconstitutional and an injunction barring the release of prisoners before the expiration of their sentences. The prosecuting attorney also sought a preliminary injunction to prevent prisoner release while this action was pending. The Kent County Office of the Defender was permitted to intervene as a defendant.
The circuit court denied the motion for a preliminary injunction, subsequently ruled that the act was constitutional, and denied the prosecutor's request for declaratory relief. The Court of Appeals reversed, and declared the act unconstitutional on the ground that it usurps the Governor's power of commutation. 133 Mich App 611; 350 NW2d 298 (1984). [425 Mich 727, n 2.]
[2]  MCL 801.52, 801.53; MSA 28.1748(2), 28.1748(3).
[3]  MCL 801.54; MSA 28.1748(4).
[4]  MCL 801.55; MSA 28.1748(5).
[5]  MCL 801.56; MSA 28.1748(6).
[6]  Irishman's Lot v Secretary of State, 338 Mich 662, 667; 62 NW2d 668 (1954).
[7]  In his concurring opinion in Rhodes v Chapman, 452 US 337, 354-355, n 3; 101 S Ct 2392; 69 L Ed 2d 59 (1981), Justice Brennan quoted from Ruiz v Estelle, 503 F Supp 1265, 1391 (SD Tex, 1980), to highlight the horrendous environments which overcrowded confinement create:

It behooves us to remember that "it is impossible for a written opinion to convey the pernicious conditions and the pain and degradation which ordinary inmates suffer within [unconstitutionally operated prisons]  the gruesome experiences of youthful first offenders forcibly raped; the cruel and justifiable fears of inmates, wondering when they will be called upon to defend the next violent assault; the sheer misery, the discomfort, the wholesale loss of privacy for prisoners housed with one, two, or three others in a forty-five foot cell or suffocatingly packed together in a crowded dormitory; the physical suffering and wretched psychological stress which must be endured by those sick or injured who cannot obtain medical care ....
"For those who are incarcerated within [such prisons], these conditions and experiences form the content and essence of daily existence."
The above conditions could equally exist with prolonged jail overcrowding.
[8]  It is significant to note that when the jail overcrowding act was passed, Governor Milliken signed it without any indication of qualms that it would invade his executive powers of clemency. House Bill 5328 (1982 PA 325) was presented to the Governor on November 24, 1982, and he signed it two weeks later, on December 8, 1982. See 1982 Journal of the House 2540, 2667-2668. Also, although the present litigation has been pending for some years, Governor Blanchard has not sought to intervene to protect his powers. It is true that a Governor does not have to join in a challenge to a statute that is said to invade his power. See, e.g., Buback v Governor, 380 Mich 209; 156 NW2d 549 (1968). Nonetheless, we can presume that each Governor recognized the need for legislation dealing with overcrowding in county jails and approved the method chosen by the Legislature to deal with this problem.
[9]  Compare Lisee v Secretary of State, 388 Mich 32, 40; 199 NW2d 188 (1972); Lansing v Jury Rowe Realty Co, 59 Mich App 316, 320; 229 NW2d 432 (1975), lv den 394 Mich 819 (1975).
[10]  legislature has created the Department of Corrections for the purpose of concentrating with that department the primary (but not exclusive of course) responsibility for the wellbeing as well as the disciplinary rehabilitation of state-sentenced prisoners.... [Green v Dep't of Corrections, 386 Mich 459, 465; 192 NW2d 491 (1971).]
[11]  See, e.g., 1979 AC, R 791.557, 791.563, 791.573, 791.574, 791.580.
[12]  In Alabama v Pugh, 438 US 781; 98 S Ct 3057; 57 L Ed 2d 1114 (1978), inmates in Alabama sued the state, its Board of Corrections, and several prison officials, asserting cruel and unusual punishment due to inhumane conditions resulting, in large part, from prison overcrowding. The United States District Court granted relief by proscribing measures to eradicate cruel and unusual punishment in the system. 406 F Supp 318 (MD Ala, 1976). The United States Court of Appeals affirmed. 559 F2d 283 (CA 5, 1977). The United States Supreme Court, while holding that the suit against Alabama and the Board of Corrections was barred by the Eleventh Amendment, declined to disturb the lower courts' ruling against the prison officials. For other cases involving 1983 actions, see footnote 1 of Justice Brennan's concurrence in Rhodes, supra, 452 US 353. See also Dickerson v Marquette Prison Warden, 99 Mich App 630; 298 NW2d 841 (1980), which presents another example of an inmate's 1983 action against a prison official, but on procedural due process grounds.
[13]  For cases holding that jails can be found liable under this exception, see, e.g., Green v Dep't of Corrections, n 10 supra; Lockaby v Wayne Co, 406 Mich 65; 276 NW2d 1 (1979); Davis v Detroit, 149 Mich App 249; 386 NW2d 169 (1986), lv den 426 Mich 856 (1986); Young v City of Ann Arbor, 119 Mich App 512; 326 NW2d 547 (1982), (On Remand), 147 Mich App 333; 382 NW2d 785 (1985), lv den 425 Mich 862 (1986).
[14]  Const 1963, art 1, § 16; US Const, Am VIII, as applied to the states through US Const, Am XIV. See Louisiana ex rel Francis v Resweber, 329 US 459; 67 S Ct 374; 91 L Ed 422 (1947); Robinson v California, 370 US 660; 82 S Ct 1417; 8 L Ed 2d 758 (1962).
[15]  In his concurrence in Rhodes v Chapman, supra, Justice Brennan noted that "individual prisons or entire prison systems in at least 24 States have been declared unconstitutional under the Eighth and Fourteenth Amendments...." 452 US 353. Justice Brennan then cited a lengthy list of cases where prisons or prison systems have been placed under court order because of conditions of confinement challenged under the Eighth and Fourteenth Amendments. See 452 US 353, n 1. In Rhodes, the United States Supreme Court reversed a finding that double celling in a state prison constituted cruel and unusual punishment. Justice Brennan, joined by Justices Blackmun and Stevens, concurred, but emphasized that the Court's decision "should in no way be construed as a retreat from careful judicial scrutiny of prison conditions...." 452 US 353.
