with whom The Chief Justice joins, dissenting.
The University of Maryland, like all state universities, differentiates in tuition between “in-state” and “out-of-state” students. The two categories of students are delineated in the University’s general policy statement on “In-State Status for Admission, Tuition, and Charge-Differential Purposes.” Part 1 of the policy statement provides:
“It is the policy of the University of Maryland to grant in-state status for admission, tuition and charge-differential purposes to United States citizens, and to immigrant *670aliens lawfully admitted for permanent residence in accordance with the laws of the United States, in the following cases:
“a. Where a student is financially dependent upon a parent, parents, or spouse domiciled in Maryland for at least six consecutive months prior to the last day available for registration for the forthcoming semester [, or]
“b. Where a student is financially independent for at least the preceding twelve months, and provided the student has maintained his domicile in Maryland for at least six consecutive months immediately prior to the last day available for registration for the forthcoming semester.” Brief for Petitioner 7 (emphasis added).
As is clear from the policy statement, domicile is not the sole criterion upon which the University of Maryland determines “in-state” tuition status. The University first looks to see whether the student is either a “United States citizen” or an “immigrant alien lawfully admitted for permanent residence” ; if the student satisfies this initial requirement, the University must then determine whether the student (or his parents) are domiciled in Maryland.
Respondents are nonimmigrant aliens who hold G-4 visas. Pursuant to the University’s tuition policy, they were denied lower in-state tuition rates despite the fact that they and their parents reside in Maryland. As explained by the Assistant Director of Admissions in a letter to respondent Clare B. Hogg, the principal reason for classifying respondents as out-of-state students for purposes of tuition was nonimmigrant status; as a secondary factor, the Assistant Director of Admissions noted that respondents would probably not be able to pass the second hurdle of domicile:1
“[T]he policy for determination of in-state status limits *671the ability to establish an in-state classification to United States citizens and immigrant aliens admitted to the United States for permanent residence. As the person ■upon whom you are dependent holds a G-4 visa, and as you hold a G-4 visa, in my judgment you are not eligible for an in-state classification.
“Also, the person upon whom you are dependent does not pay Maryland income tax on all earned income, including income earned outside the state. I feel this further weakens your request for reclassification as this is an important criteria in determination of domicile.” Record 106.
Respondents brought suit in federal court alleging that the University’s in-state tuition policy is, among other things, in violation of the Due Process and Equal Protection Clauses of the Fourteenth Amendment. The District Court for the District of Maryland held that the University’s policy creates an irrebuttable presumption in contravention of Vlandis v. Kline, 412 U. S. 441 (1973). The Court of Appeals for the Fourth Circuit affirmed. We granted certiorari to decide whether the lower courts were correct in their holding.
The Court, rather than deciding the due process issue upon *672which certiorari was granted, today certifies the following question to the Court of Appeals of Maryland: 2
“Are persons residing in Maryland who hold or are named in a visa under 8 U. S. C. § 1101 (a) (15) (G) (iv) (1976 ed.), or who are financially dependent upon a person holding or named in such a visa, incapable as a matter of state law of becoming domiciliaries of Maryland?”
I would unhesitatingly join the Court’s certification if I felt that resolution of the question posed to the Court of Appeals of Maryland were necessary to decide the issue before us. But I am convinced that we can decide the due process issue without resolution of Maryland domicile law and thus that certification will only result in needless delay.
The University apparently classifies nonimmigrant aliens as out-of-state students for a number of- reasons. All parties agree that a major factor is the University’s conclusion that nonimmigrant aliens lack the legal capacity to become Maryland domiciliaries for tuition purposes. But this is not the only consideration underlying the classification, as is evidenced by the fact that citizenship or immigrant status is a requirement separate from and preceding domicile. According to *673the President of the University of Maryland, for example, the classification policy also “reflects the desire to equalize, as far as possible, the cost of education between those who support the University of Maryland through payment of the full spectrum of Maryland taxes, and those who do not.” App. 12A. Holders of G-4 nonimmigrant visas are exempt from state income tax. By charging such nonimmigrant aliens higher out-of-state tuition, the University is able to better “equalize” the cost of education.3
Because the University’s conclusion as to domicile plays a major role in its decision not to award nonimmigrant aliens in-state tuition status, counsel for petitioner admitted at oral argument that “it is entirely possible that the university would change its policy” in the face of a contrary decision by the Maryland Court of Appeals. Tr. of Oral Arg. 9. But a change in the University’s in-state tuition policy would be neither automatic nor inescapable. The University might still decide that the other considerations such as cost equalization by themselves dictate continuation of the current policy. According to counsel for petitioner, “that judgment is one that would be made by the regents, and [as] I have suggested previously ... it is well within the discretion of the regents.” Id., at 15.
The above facts clearly establish that the University of Maryland has not created an irrebuttable presumption. The University has not determined that domicile is the sole relevant factor in determining tuition rates and then prevented respondents from presenting proof on the question of domicile.4 *674Instead, the University has decided that, for a number of reasons including domicile and cost equalization, nonimmigrant aliens should pay a higher tuition rate than citizens and *675immigrant aliens who are domiciled in the State. A student is allowed to present any and all evidence relevant to his or her status as a citizen or immigrant alien. In Vlandis v. Kline, this Court held only that where a State “purport [s] to be concerned with residency, it might not at the same time deny to one seeking to meet its test of residency the opportunity to show factors clearly bearing on that issue. 412 U. S., at 452.” Weinberger v. Salfi, 422 U. S. 749, 771 (1975) (emphasis added).5 Here, the University of Maryland’s classification policy
“does not purport to speak in terms of the bona fides of [domicile], but then make plainly relevant evidence of such bona fides inadmissible. As in Starns v. Malkerson, 326 F. Supp. 234 (Minn. 1970), summarily aff’d, 401 U. S. 985 (1971), the benefits here are available upon compliance with an objective criterion, one which the Legislature considered to bear a sufficiently close nexus with underlying policy objectives to be used as the test for eligibility. Like the plaintiffs in Starns, [respondents] are completely free to present evidence that they meet the specified requirements; failing in this effort, their only constitutional claim is that the test they cannot meet is not so rationally related to a legitimate legislative objective that it can be used to deprive them of benefits available to those who do satisfy that test.” Id., at 772.
Because it is clear that the University of Maryland has not created an irrebuttable presumption of non-Maryland domicile, it is unnecessary to decide, as the Court apparently believes *676it is, whether “any ‘irrebuttable presumption’ would be universally true.” Ante, at 661. And while the case may become moot if the Court of Appeals of Maryland decides that holders of G-4 visas can establish Maryland domicile and if the University changes its policy in light of that decision, the case is not moot now and there is no certainty that it will become moot in the future. There is, in summary, nothing today that prevents the Court from deciding the question presented.6
*677While I cannot join in what I view as a needless and time-consuming certification, I do join in the Court’s implied disapproval of the District Court’s refusal to refer to Maryland courts the question of whether holders of G-4 visas can establish Maryland domicile. Upon concluding that the University’s policy creates an irrebuttable presumption, the District Court was faced with the question of whether the presumption is universally true. The District Court proceeded to answer the question in the negative and enjoin the University’s policy, even though petitioner had asked the District Court either to abstain or, apparently, to certify the question of domicile to the Court of Appeals of Maryland.7 Because the Court of Appeals of Maryland had never addressed the question of domicile, petitioner’s request should have been granted. By *678deciding the question itself, the District Court risked invalidating a state policy that a later decision of the Maryland state courts might establish was clearly valid. Furthermore, as the Court emphasizes, “it is obviously desirable that questions of law which, like domicile, are both intensely local and immensely important to a wide spectrum of state government activities be decided in the first instance by state courts.” Ante, at 663 n. 16.
In summary, I agree with the Court that important and controlling issues of state law should initially be decided by state, not federal, courts. But because I do not believe that resolution of the Maryland law of domicile is necessary to decide the due process question before us, I dissent from today’s certification.8
In rejecting the appeals of respondents Moreno and Otero from tuition *671decisions of the Intercampus Review Committee, petitioner President of the University of Maryland also emphasized that the University precludes nonimmigrant aliens from in-state tuition status for reasons other than solely domicile:
“It is the policy of the University of Maryland to grant in-state status for admission, tuition and charge-differential purposes only to United States citizens and to immigrant aliens lawfully admitted for permanent residence. Furthermore, such individuals (or their parents) must display Maryland domicile. . . .
“The University’s classification -policy also distinguishes between domiciliaries and non-domiciliaries of Maryland.” App. 12A (emphasis added).
See also Record 34, 55, 80, and 115.
As the Court notes, ante, at 668-669, n. 28, the question certified to the Court of Appeals of Maryland may not be answerable by a simple “yes” or “no.” The Court asks as a general matter whether respondents are “incapable as a matter of state law of becoming domiciliaries of Maryland.” The answer may be that they are incapable of establishing Maryland domicile for university tuition purposes but are still capable of becoming domiciliaries for other purposes such as divorce and personal jurisdiction. While in Williamson v. Osenton, 232 U. S. 619, 625 (1914), this Court expressed doubt whether the definition of domicile ever varies depending on the purpose for which domicile is being used, various state-court opinions since 1914-have shown that observation to be incorrect. See, e. g., In re Estate of Jones, 192 Iowa 78, 82, 182 N. W. 227, 229 (1921). The relevant issue in this case, of course, is whether respondents may establish Maryland domicile for university purposes, not whether they may become domiciled for purposes of divorce, etc.
As the Court recognizes, ante, at 656-657, n. 5, the University of Maryland does not presently preclude students from in-state tuition status solely because their parents pay no state income tax. However, the record clearly demonstrates that cost equalization is one of the major concerns that have led the University to charge higher tuition rates to nonimmigrant aliens.
The Court does not appear to argue that domicile is the sole reason for the University of Maryland’s out-of-state classification of nonimmigrant aliens. Instead, the Court concludes that domicile is the “ 'paramount’ *674and controlling concern” of the University. Ante, at 659, and n. 8. The Court supports its conclusions not with citations from the pleadings or affidavits of the parties but with references to briefs and memoranda filed by their counsel. Counsel for petitioner is, of course, charged with the legal defense of the validity of the policy statement promulgated by the Board of Regents and enforced by petitioner, but counsel is not authorized, in the absence of more authority than is shown here, either to rewrite or to predict how the Regents might rewrite its policy. Thus whatever the “surprise” that the Court foresees petitioner will experience from the view taken of the Regents’ policy statement, see ante, at 659 n. 8, will stem not from this dissent but from the Court’s willingness to attribute to ambiguous statements by counsel for a state agency the implied authority to rewrite the agency’s regulations or to predict the manner in which the agency might rewrite them. Even the selected statements of counsel do not unequivocally support the Court’s conclusion. As noted earlier, supra, at 673, while counsel for petitioner suggested that “the odds are reasonably high” that the University will modify its policy if the Court of Appeals of Maryland concludes that G-4 aliens can become domiciled in Maryland, he also emphasized that the University's other concerns, such as cost equalization, might lead the Regents to continue out-of-state classification of nonimmigrant aliens. Domicile, in other words, is not the sole concern of the University and may well not even be a “controlling concern.” See also Brief for Petitioner 29-32; Tr. of Oral Arg. 19-21 (out-of-state classification of nonimmigrant aliens “serve[s] many purposes other than measuring domicile”; “the policy ... is clearly intended to serve other purposes”).
Even if the University declined to accord in-state tuition status to nonimmigrant aliens solely because of the University’s conclusion that non-immigrant aliens cannot be domiciled in Maryland for tuition purposes, no irrebuttable presumption would be presented. In Vlandis v. Kline, 412 U. S. 441 (1973), the University presumed that a student who was not domiciled in Connecticut at the time he first enrolled at the University of Connecticut could not become a Connecticut resident while attending the University, even though all the normal indicia of residence might be acquired during this period. Here, on the other hand, the University of Maryland merely reads Maryland law as holding that nonimmigrant G-4 aliens cannot satisfy the requirement for Maryland domicile for tuition purposes. This is purely and simply a question of state law. Respondents *675do not accuse petitioner of employing a nonuniversal, yet irrebuttable, presumption, but rather of misinterpreting Maryland domicile law. If the University of Maryland has misinterpreted state law, this is an error to be resolved by state, not federal, courts; no issue of federal constitutional law is presented.
Because the tuition policy of the University of Maryland is controlled by Weinberger v. Salfi and not Vlandis v. Kline, the Court need not decide, as amici 29 States urge us to do, whether Vlandis should be overruled.
Some Members of the Court- may believe that resolution of the state domicile issue would be helpful in resolving respondents’ equal protection claim. If t-he Court of Appeals of Maryland decides that nonimmigrant aliens holding G-4 visas cannot establish Maryland domicile for tuition purposes, Starns v. Malkerson, 326 F. Supp. 234 (Minn. 1970), summarily aff’d, 401 U. S. 985 (1971), clearly establishes that the University of Maryland can deny such nondomiciliaries lower in-state tuition rates without violating the Equal Protection Clause of the Fourteenth Amendment. If the Court of Appeals decides that holders of G-4 visas can establish Maryland domicile, on the other hand, resolution of respondents’ equal protection claim may rest on the proper interpretation of Nyquist v. Mauclet, 432 U. S. 1 (1977).
The only question presented by the petition for certiorari, however, is: “Whether the decisions below should have applied Supreme Court precedents on irrebuttable presumptions, disregarded the principles articulated in Weinberger v. Salfi, 422 U. S. 749 (1975), and erroneously concluded that the University of Maryland’s policy of denying in-state status for tuition and fee purposes to non-immigrants holding G-4 visas establishes an irrebuttable presumption violative of the due process clause of the fourteenth amendment to the United States Constitution?” Consideration of respondents’ equal protection claim, which was never addressed below, may best be left initially to the lower courts on remand. Even if the Court ultimately decides to consider respondents’ equal protection arguments, resolution of Maryland domicile law would seem irrelevant. Unlike the situation in Nyquist, the University of Maryland does not discriminate against resident aliens. Cf. 432 U. S., at 2, 4, 5-6, and n. 6, and 12. There thus would not appear to be any issue of suspect class and the University’s in-state tuition policy need only be shown to be rationally related to a legitimate state interest. The University’s concern with cost equalization alone would seem sufficient to support the line drawn by the University. See Starns v. Malkerson, supra.
According to petitioner, he “urged both the district court and the court of appeals to defer to Maryland courts the question of whether the state law precluded G-4’s from establishing Maryland domicile.” Brief for Petitioner 35 n. 20. The record indicates that petitioner, in his answer to respondents’ complaint, urged the District Court to “abstain from exercising any jurisdiction it may possess in this action until it shall have been heard and determined fully by the courts of Maryland.” Record 117. Petitioner renewed the request in his motion for summary judgment and memorandum in support thereof. Id., at 211, and 239-243. In reply, respondents urged the District Court, “should [it] elect to abstain, . . . to use the certification procedure provided by the Uniform Certification of Questions of Law Act, Ann. Code of Md., Courts and Judicial Proceedings, §§ 12-601-609 (1974). Under that Act the Court of Appeals of Maryland is empowered to answer questions of state law certified to it by the United States District Court which may be determinative and as to which it appears there is no controlling precedent.” Id., at 274. Respondents also went on to argue, however, that the District Court need neither abstain outright nor certify the question of domicile to the Court of Appeals of Maryland, since “the Maryland common law of domicile is not at issue in this case. No 'clarification’ of the Maryland common law of domicile is needed.” Id., at 272. The District Court, although concluding that the Maryland law of domicile is relevant, declined to either abstain outright or certify the question of domicile to the Court of Appeals of Maryland.
While I agree with the Court’s conclusion that holders of G-4 visas are not prevented as a matter of federal law from establishing Maryland domicile, I find it unnecessary to address the five pages of dicta that accompany that conclusion. I am nonetheless troubled by the Court’s unsupported dictum that the United States may not be able to deport, under certain unspecified circumstances, a G-4 alien who terminates his employment with an international treaty organization. Ante, at 667.