Four Missouri state court judges challenge the provision of the Missouri Constitution that mandates their retirement at age 70. Mo. Const, art. V, § 26(1) (1945 as amended 1976) (“mandatory retirement provision”). Judges Ellis Gregory, Jr., Anthony P. Nugent, Jr., and Douglas W. Greene, argue that the mandatory retirement provision violates the federal Age Discrimination in Employment Act (“ADEA”), 29 U.S.C. §§ 621-634 (1982 & Supp.1987). These judges along with Judge Flake L. McHaney further argue that the mandatory retirement provision violates the equal protection clause of the Fourteenth Amendment.
Judges Gregory, Nugent, and Greene were initially appointed and have been retained as judges pursuant to the Missouri Non-Partisan Court Plan (“Missouri Plan”). Mo. Const, art. V, § 25. Under the Missouri Plan, the Governor (selecting from candidates recommended by merit screening commissions) appoints judges to the state supreme court, to the state intermediate appellate court, and to the state circuit courts within Jackson County (which encompasses Kansas City) and the city of St. Louis. At the end of his appointed term, each judge must place his name on the ballot in the next general election if he wishes to be retained for another term. If a majority of the voters vote in favor of retaining the judge in office, he serves another full term on the bench. At the end of that term, the judge again may place his name on the ballot and be retained for yet another full term; except for the mandatory retirement provision, there is no limit on the number of terms a judge may achieve through this ballot-retention method. The judges selected according to the Missouri Plan argue that they are “employees” entitled to the protection of the ADEA because they are neither “elected to public office” nor “appointee[s] on the policymaking level.” See 29 U.S.C. § 630(f). 1
The District Court 2 granted Governor John D. Ashcroft’s motion to dismiss after determining that Judges Gregory, Nugent, and Greene were excluded from the ADEA definition of “employee” because they are “appointee[s] on the policymaking level,” 29 U.S.C. § 630(f), and that the mandatory retirement provision does not violate the Fourteenth Amendment because there is a rational basis for this provision. The judges appeal. We affirm.
I.
The statutory claim of Judges Gregory, Nugent, and Greene arises out of an asserted conflict between the ADEA, 29 U.S.C. § 621-634, and the provision of the Missouri Constitution that requires judges to retire upon reaching the age of 70. Subject to several exceptions discussed below, the ADEA prohibits an employer from discriminating on the basis of age in making virtually any employment decision regarding an employee who is 40 or more years of age. 29 U.S.C. §§ 623, 631. In 1976, when the mandatory retirement provision was added to the Missouri constitution, it was unaffected by the ADEA, which at that time applied only to employees between the *600 ages of 40 and 65. In 1978, Congress raised the age limit of 65 to 70, and in 1986 (effective January 1, 1987), it eliminated the upper age limit and amended the ADEA to cover all employees having reached the age of 40. See 29 U.S.C. § 631(a).
It is undisputed that if the definition of “employee” contained in the ADEA extends to Judges Gregory, Nugent, and Greene, the application to them of the mandatory retirement provision would be a violation of the Act. Under the supremacy clause of the United States Constitution, a conflict between a constitutionally valid federal law and state law must be resolved in favor of the federal law.
See
U.S. Const, art. VI, cl. 2. Thus, “to the extent that the [ADEA] conflict[s] with existing state mandatory retirement statutes, the Supremacy Clause dictates that federal law prevail.”
Orzel v. City of Wauwatosa Fire Dep’t,
We now turn to the language of the statute. The central issue is whether the “except” clause in the ADEA definition of “employee” applies to appointed state court judges and thereby excludes them from the protection of the Act.
The term “employee” means an individual employed by any employer except that the term “employee” shall not include any person elected to public office in any State or political subdivision of any State by the qualified voters thereof, or any person chosen by such officer to be on such officer’s personal staff, or an appointee on the policymaking level or an immediate advisor with respect to the exercise of the constitutional or legal powers of the office.
29 U.S.C. § 630(f) (emphasis added).
As a preliminary matter, we note that the District Court found Judges Gregory, Nugent, and Greene, initially appointed by the Governor and retained in office by a majority of the voters as required by the Missouri Plan, to be outside the ADEA’s exception for persons “elected to public office”. Although we are inclined to disagree with this aspect of the District Court’s decision, the Governor did not cross-appeal this issue, it was not briefed by either side, and it is not properly before us. We therefore express no opinion on this point, and shall assume for the balance of this opinion that state judges selected according to the Missouri Plan are appointed and not “elected” within the meaning of the ADEA. 3
*601
It follows that our task is to determine whether appointed state judges are “ap-pointeefs] on the policymaking level.” A handful of federal and state courts have addressed this issue.
See EEOC v. Massachusetts,
Appellants urge us to adopt the reasoning and holding of the district courts in
Vermont
and
Schlitz.
They argue that a literal reading of the “policymaking level” exception supports their position because the principal function of a judge is not to make policy, but rather to “decide cases between litigants involving questions of law in which there are no interstices or lacunae to fill.”
Vermont,
“[Pjolicymaking” is indisputably a part of the function of judging to the extent that judging involves lawmaking to fill the interstices of authority found in constitutions, statutes, and precedents.... Moreover, the substantive interest identified by the phrase “on the policymaking level” is closely aligned with an interest referred to by phrases such as “exercise of discretion” and “exercise of judgment,” which are indisputably descriptive of most of the performance of those persons within the judicial branch who serve as judges....
EEOC v. Massachusetts,
Furthermore, many of Missouri’s appointed judges exercise considerable policy-making responsibility in the supervision of the Missouri court system. The three levels of the Missouri courts are administered by the Chief Justice of the Supreme Court, the Chief Judges of the various divisions of the court of appeals, and the Presiding Judges in the circuit courts, each having general supervisory powers. Mo. Const, art. V, § 4. The Missouri Supreme Court is responsible for adopting the rules governing the professional conduct of the Missouri judiciary and the Missouri Bar. Moreover, the Missouri Supreme Court is responsible for resolving disputes within the judicial hierarchy.
See In re Rules of Circuit Court for Twenty-First Judicial Circuit,
Appellants claim that the context of the exception for an “appointee on the policy-making level”, placed as it is within a series of exemptions which apply primarily to the executive and legislative branches of government, indicates that it applies exclusively to appointees within these two branches of government and not to appointees within the judiciary. Appellant’s Brief at 11-12. We do not agree. If the policy-making level exception is read in this limited manner, none of the four categories of exemptions from the coverage of the ADEA would apply to employees in the judicial branch in those states where judges are appointed. We believe it is highly unlikely that Congress intended this result, and the implausibility of the total exclusion of the appointed members of the state judiciary from any exemption under the ADEA, despite the total exemption of elected judges from the coverage of the Act, weighs heavily against such a narrow reading of the policymaking level exception.
See EEOC v. Massachusetts,
Appellants base their argument in part on legislative history of the exemptions set forth in section 630(f) of the ADEA:
[i]t is the intention of the conferees to exempt elected officials and members of their personal staff, and persons appointed by such elected officials as advisors or to policymaking positions at the highest levels of the departments or agencies of State or local governments, such as cabinet officers, and persons with comparable responsibilities at the local level. It is the conferees intent that this exemption shall be construed narrowly.
Joint Explanatory Statement of Managers at the Conference on H.R. 1746, 92d Cong., 1st Sess., reprinted in 1972 U.S. Code Cong. & Admin.News 2179-2180. Relying on this snippet of legislative history (which we are not inclined to assign a great deal of weight, since the only reliable guide to legislative intent is the language and structure of the statute itself), appellants argue that the state courts cannot be considered agencies of state or local government. See Appellant’s Brief at 13. We disagree. It seems to us far more realistic to view the state judiciary as one of the more powerful “agencies” of state government. The term “government” in this country traditionally has implied the tripartite of the executive, legislative, and judicial branches. We are not persuaded that the language quoted above indicates that Congress clearly intended the “appointee on the policymaking level” exemption in Section 630(f) to apply only to individuals in the executive and the legislative branches. In our view, this legislative history proves little. If anything, it suggests that the conferees simply were *603 not thinking about state judges when they adopted the short statement upon which appellants rely.
If we were to read the “appointee on the policymaking level” exemption as appellants urge us to, we would be left with the anomalous result that low-level employees in the executive and legislative branches would be excluded from the ADEA’s coverage if they were on the personal staff of an elected official, while the highest ranking officials in the judicial branch — the judges (but only when appointed rather than elected) — were included within the ADEA’s umbrella. As another court noted:
the resulting line between those who are and those who are not “employees” would be not merely a somewhat wavering line because of the different characteristics and different sets of interests identified by the four different categories in the “except” clause but, more strikingly, a line jumping sharply up or down as to levels of authority and levels of discretionary performance, depending on whether one served in an elective office (in which case even lower tier officers would be excepted, in all three branches of government) or an appointive office (in which case persons serving in discretionary or advisory positions would be covered in the judicial branch and excepted in the other two branches).
EEOC v. Massachusetts,
In Missouri, where the majority of state judges are elected, the irrationality of not excluding appointed judges from the ADEA as “appointee[s] on the policymak-ing level” is even more pronounced. There is simply no principled basis for treating Missouri’s appointed judges differently from its elected judges for purposes of the ADEA.
5
EEOC v. Massachusetts,
Finally, appellants argue that this Court’s decision in
Stillians v. Iowa,
For the reasons stated above, we hold that judges appointed under the Missouri Plan are excluded from the coverage of the ADEA because they are “appointee[s] on the policymaking level” within the meaning of 29 U.S.C. § 630(f).
II.
All four of the judges contend that the Missouri mandatory retirement provision for state court judges violates the equal protection clause of the Fourteenth Amendment. 6 We do not agree and note that we are unable to find even a single case wherein a state mandatory retirement provision has been invalidated under the Fourteenth Amendment.
Appellants concede that because legislation addressed toward persons over the age of 70 is not subject to heightened scrutiny for constitutional infirmity, our review of the Missouri mandatory retirement provision is confined to determining whether it rationally furthers a legitimate state purpose.
See Massachusetts Bd. of Retirement v. Murgia,
Appellants’ argument that an evidentiary hearing is required on the rational-basis issue is without merit. In
Pennell v. City of San Jose,
As we stated in Vance v. Bradley,440 U.S. 93 , 99 [99 S.Ct. 939 , 944,59 L.Ed.2d 171 ] (1979), “we will not overturn [a statute that does not burden a suspect class or a fundamental interest] unless the varying treatment of different groups or persons is so unrelated to the achievement of any combination of legitimate purposes that we can only conclude that the legislature’s actions were irrational.”
Id.
[t]he lesson of Murgia is that where individuals in the group affected by a law have distinguishing characteristics relevant to interests the State has the authority to implement, the courts have been very reluctant, as they should be in our federal system and with our respect for the separation of powers, to closely scrutinize legislative choices as to whether, how, and to what extent those interests should be pursued. In such cases, the Equal Protection Clause requires only a rational means to serve a legitimate end.
Cleburne,
Our task, then, is to determine whether the mandatory retirement provision is a rational method by which Missouri may serve its legitimate goal of maintaining a highly qualified and vigorous state judiciary. The Missouri Supreme Court considered this issue in
O’Neil v. Baine,
Because we cannot say that Missouri’s mandatory retirement provision for state judges lacks a rational basis, we affirm the District Court’s determination that the provision does not violate the equal protection clause of the Fourteenth Amendment.
The judgment of the District Court is affirmed.
Notes
. The parties do not dispute that Judge McHa-ney, elected to office in a traditional partisan election, does not fall within the coverage of the ADEA. See 29 U.S.C. § 630(f) ("term ‘employee’ shall not include any person elected to public office ...").
. The Honorable William L. Hungate, United States District Judge for the Eastern District of Missouri.
. Interestingly, the EEOC has taken the position that a state judge "who is appointed by the governor or the legislature but must appear on a ballot before the general electorate for either retention or rejection would be excepted from the term ‘employee' under the ADEA as a ‘person elected to public office.’ ” EEOC Opinion Letter to Rep. Claude Pepper, April 7, 1987, reprinted in EEOC Compliance Man. (BNA) at N:1001, n. 2.
. The decisions of the Missouri Supreme Court establish common law for the entire state.
See, e.g., Gustafson v. Benda,
. The EEOC argues that states which elect their judges have decided to make them policymakers, responsive to the voters, while states with an appointed bench have chosen to "insulate[ ] [it] from the political process to which those who make governmental policy are subjected.” Brief for EEOC as amicus curiae at 9. This argument is unconvincing. The powers and responsibilities of appointed and elected judges are identical and it is these powers and responsibilities that determine whether a judge is on the "policymaking level."
. Appellants also claim that the mandatory retirement provision violates the due process clause. We take this to be a substantive due process claim. Appellants have not articulated, however, what fundamental right Missouri’s mandatory retirement provision denies them and we therefore will not address this issue. If they are claiming a fundamental right to retain their judgeships after age 70, we categorically reject the notion that the Constitution provides any such right.
See Massachusetts Bd. of Retirement v. Murgia,
