Justice White
delivered the opinion of the Court.
Appellants challenge the constitutionality of the Hawaii liquor tax, which is a 20% excise tax imposed on sales of liquor at wholesale. Specifically at issue are exemptions from the tax for certain locally produced alcoholic beverages. The Supreme Court of Hawaii upheld the tax against challenges based upon the Equal Protection Clause, the Import-Export Clause, and the Commerce Clause. In re Bacchus Imports, Ltd., 65 Haw. 566, 656 P. 2d 724 (1982). We noted probable jurisdiction sub nom. Bacchus Imports, Ltd. v. Freitas, 462 U. S. 1130 (1983), and now reverse.
I — I
The Hawaii liquor tax was originally enacted in 1939 to defray the costs of police and other governmental services that the Hawaii Legislature concluded had been increased due to the consumption of liquor. At its inception the statute contained no exemptions. However, because the legislature sought to encourage development of the Hawaiian liquor industry, it enacted an exemption for okolehao from May 17, 1971, until June 20, 1981, and an exemption for fruit wine from May 17, 1976, until June 30, 1981. Haw. Rev. Stat. §§244-4(6), (7) (Supp. 1983). Okolehao is a brandy distilled from the root of the ti plant, an indigenous shrub of Hawaii. In re Bacchus Imports, Ltd., supra, at 569, n. 7, 656 P. 2d, at 727, n. 7. The only fruit wine manufactured in Hawaii during the relevant time was pineapple wine. Id., at 570, n. 8, 656 P. 2d, at 727, n. 8. Locally produced sake and fruit liqueurs are not exempted from the tax.
Appellants — Bacchus Imports, Ltd., and Eagle Distributors, Inc. — are liquor wholesalers who sell to licensed retailers. They sell the liquor at their wholesale price plus the 20% excise tax imposed by §244-4, plus a one-half percent tax imposed by Haw. Rev. Stat. §237-13 (Supp. 1983). Pursuant to Haw. Rev. Stat. §40-35 (Supp. 1983), which authorizes a taxpayer to pay taxes under protest and to commence an action in the Tax Appeal Court for the recovery of disputed sums, the wholesalers initiated protest proceedings and sought refunds of all taxes paid. Their complaint alleged that the Hawaii liquor tax was unconstitutional because it violates both the Import-Export Clause and the Commerce Clause of the United States Constitution. The wholesalers sought a refund of approximately $45 million, representing all of the liquor tax paid by them for the years in question.
The Tax Appeal Court rejected both constitutional claims. On appeal, the Supreme Court of Hawaii affirmed the decision of the Tax Appeal Court and rejected an equal protection challenge as well. It held that the exemption was rationally related to the State’s legitimate interest in promoting domestic industry and therefore did not violate the Equal Protection Clause. 65 Haw., at 573, 656 P. 2d, at 730. It further held that there was no violation of the Import-Export Clause because the tax was imposed on all local sales and uses of liquor, whether the liquor was produced abroad, in sister States, or in Hawaii itself. Id., at 578-579, 656 P. 2d, at 732-733. Moreover, it found no evidence that the tax was applied selectively to discourage imports in a manner inconsistent with federal foreign policy or that it had any substantial indirect effect on the demand for imported liquor. Ibid. Turning to the Commerce Clause challenge, the Hawaii court held that the tax did not illegally discriminate against interstate commerce because “incidence of the tax ... is on wholesalers of liquor in Hawaii and the ultimate burden is borne by consumers in Hawaii.” Id., at 581, 656 P. 2d, at 734.
II
The State presents a claim not made below that the wholesalers have no standing to challenge the tax because they have shown no economic injury from the claimed discriminatory tax. The wholesalers are, however, liable for the tax. Although they may pass it on to their customers, and attempt to do so, they must return the tax to the State whether or not their customers pay their bills. Furthermore, even if the tax is completely and successfully passed on, it increases the price of their products as compared to the exempted beverages, and the wholesalers are surely entitled to litigate whether the discriminatory tax has had an adverse competitive impact on their business. The wholesalers plainly have standing to challenge the tax in this Court.
III
A cardinal rule of Commerce Clause jurisprudence is that “[n]o State, consistent with the Commerce Clause, may ‘impose a tax which discriminates against interstate commerce . . . by providing a direct commercial advantage to local business/” Boston Stock Exchange v. State Tax Comm’n, 429 U. S. 318, 329 (1977) (quoting Northwestern States Portland Cement Co. v. Minnesota, 358 U. S. 450, 458 (1959)). Despite the fact that the tax exemption here at issue seems clearly to discriminate on its face against interstate commerce by bestowing a commercial advantage on okolehao and pineapple wine, the State argues — and the Hawaii Supreme Court held — that there is no improper discrimination.
A
Much of the State’s argument centers on its contention that okolehao and pineapple wine do not compete with the other products sold by the wholesalers. The State relies in part on statistics showing that for the years in question sales of okolehao and pineapple wine constituted well under one percent of the total liquor sales in Hawaii. It also relies on the statement by the Hawaii Supreme Court that “[w]e believe we can safely assume these products pose no competitive threat to other liquors produced elsewhere and consumed in Hawaii,” In re Bacchus Imports, Ltd., 65 Haw., at 582, n. 21, 656 P. 2d, at 735, n. 21, as well as the court’s comment that it had “good reason to believe neither okolehao nor pineapple wine is produced elsewhere.” Id., at 582, n. 20, 656 P. 2d, at 735, n. 20. However, neither the small volume of sales of exempted liquor nor the fact that the exempted liquors do not constitute a present “competitive threat” to other liquors is dispositive of the question whether competition exists between the locally produced beverages and foreign beverages; instead, they go only to the extent of such competition. It is well settled that “[w]e need not know how unequal the Tax is before concluding that it unconstitutionally discriminates.” Maryland v. Louisiana, 451 U. S. 725, 760 (1981).
The State’s position that there is no competition is belied by its purported justification of the exemption in the first place. The legislature originally exempted the locally produced beverages in order to foster the local industries by encouraging increased consumption of their product. Surely one way that the tax exemption might produce that result is that drinkers of other alcoholic beverages might give up or consume less of their customary drinks in favor of the exempted products because of the price differential that the exemption will permit. Similarly, nondrinkers, such as the maturing young, might be attracted by the low prices of okolehao and pineapple wine. On Hie stipulated facts in this case, we are unwilling to conclude that no competition exists between the exempted and the nonexempted liquors.
B
The State contends that a more flexible approach, taking into account the practical effect and relative burden on commerce, must be employed in this case because (1) legitimate state objectives are credibly advanced, (2) there is no patent discrimination against interstate trade, and (3) the effect on interstate commerce is incidental. See Philadelphia v. New Jersey, 437 U. S. 617, 624 (1978). On the other hand, it acknowledges that where simple economic protectionism is effected by state legislation, a stricter rule of invalidity has been erected. Ibid. See also Minnesota v. Clover Leaf Creamery Co., 449 U. S. 456, 471 (1981); Lewis v. BT Investment Managers, Inc., 447 U. S. 27, 36-37 (1980).
A finding that state legislation constitutes “economic protectionism” may be made on the basis of either discriminatory purpose, see Hunt v. Washington Apple Advertising Comm’n, 432 U. S. 333, 352-353 (1977), or discriminatory effect, see Philadelphia v. New Jersey, supra. See also Minnesota v. Clover Leaf Creamery Co., supra, at 471, n. 15. Examination of the State’s purpose in this case is sufficient to demonstrate the State’s lack of entitlement to a more flexible approach permitting inquiry into the balance between local benefits and the burden on interstate commerce. See Pike v. Bruce Church, Inc., 397 U. S. 137, 142 (1970). The Hawaii Supreme Court described the legislature’s motivation in enacting the exemptions as follows:
“The legislature’s reason for exempting Ti root okolehao’ from the ‘alcohol tax’ was to ‘encourage and promote the establishment of a new industry,’ S. L. H. 1960, c. 26; Sen. Stand. Comm. Rep. No. 87, in 1960 Senate Journal, at 224, and the exemption of ‘fruit wine manufactured in the State from products grown in the State’ was intended ‘to help’ in stimulating ‘the local fruit ■wine industry.’ S. L. H. 1976, c. 39; Sen; Stand. Comm. Rep. No. 408-76, in 1976 Senate Journal, at 1056.” In re Bacchus Imports, Ltd., supra, at 573-574, 656 P. 2d, at 780.
Thus, we need not guess at the legislature’s motivation, for it is undisputed that the purpose of the exemption was to aid Hawaiian industry. Likewise, the effect of the exemption is clearly discriminatory, in that it applies only to locally produced beverages, even though it does not apply to all such products. Consequently, as long as there is some competition between the locally produced exempt products and nonexempt products from outside the State, there is a discriminatory effect.
No one disputes that a State may enact laws pursuant to its police powers that have the purpose and effect of encouraging domestic industry. However, the Commerce Clause stands as a limitation on the means by which a State can constitutionally seek to achieve that goal. One of the fundamental purposes of the Clause “was to insure . . . against discriminating State legislation.” Welton v. Missouri, 91 U. S. 275, 280 (1876). In Welton, the Court struck down a Missouri statute that “discriminat[ed] in favor of goods, wares, and merchandise which are the growth, product, or manufacture of the State, and against those which are the growth, product, or manufacture of other states or countries. . . .” Id., at 277. Similarly, in Walling v. Michigan, 116 U. S. 446, 455 (1886), the Court struck down a law imposing a tax on the sale of alcoholic beverages produced outside the State, declaring:
“A discriminating tax imposed by a State operating to the disadvantage of the products of other States when introduced into the first mentioned State, is, in effect, a regulation in restraint of commerce among the States, and as such is a usurpation of the power conferred by the Constitution upon the Congress of the United States.”
See also I. M. Darnell & Son Co. v. Memphis, 208 U. S. 113 (1908).
More recently, in Boston Stock Exchange v. State Tax Comm’n, 429 U. S. 318 (1977), the Court struck down a New York law that imposed a higher tax on transfers of stock occurring outside the State than on transfers involving a sale within the State. We observed that competition among the States for a share of interstate commerce is a central element of our free-trade policy but held that a State may not tax interstate transactions in order to favor local businesses over out-of-state businesses. Thus, the Commerce Clause limits the manner in which States may legitimately compete for interstate trade, for “in the process of competition no State may discriminatorily tax the products manufactured or the business operations performed in any other State.” Id., at 337. It is therefore apparent that the Hawaii Supreme Court erred in concluding that there was no improper discrimination against interstate commerce merely because the burden of the tax was borne by consumers in Hawaii.
The State attempts to put aside this Court’s cases that have invalidated discriminatory state statutes enacted for protectionist purposes. See Minnesota v. Clover Leaf Creamery Co., supra, at 471; Lewis v. BT Investment Managers, Inc., supra, at 36-37. The State would distinguish these cases because they all involved attempts “to enhance thriving and substantial business enterprises at the expense of any foreign competitors.” Brief for Appellee Dias 30. Hawaii’s attempt, on the other hand, was “to subsidize nonexistent (pineapple wine) and financially troubled (okolehao) liquor industries peculiar to Hawaii.” Id., at 33. However, we perceive no principle of Commerce Clause jurisprudence supporting a distinction between thriving and struggling enterprises under these circumstances, and the State cites no authority for its proposed distinction. In either event, the legislation constitutes “economic protectionism” in every sense of the phrase. It has long been the law that States may not “build up [their] domestic commerce by means of unequal and oppressive burdens upon the industry and business of other States.” Guy v. Baltimore, 100 U. S. 434, 443 (1880). Were it otherwise, “the trade and business of the country [would be] at the mercy of local regulations, having for their object to secure exclusive benefits to the citizens and products of particular States.” Id., at 442. It was to prohibit such a “multiplication of preferential trade areas” that the Commerce Clause was adopted. Dean Milk Co. v. Madison, 340 U. S. 349, 356 (1951). Consequently, the propriety of economic protectionism may not be allowed to hinge upon the State’s — or this Court’s — characterization of the industry as either “thriving” or “struggling.”
We also find unpersuasive the State’s contention that there was no discriminatory intent on the part of the legislature because “the exemptions in question were not enacted to discriminate against foreign products, but rather, to promote a local industry.” Brief for Appellee Dias 40. If we were to accept that justification, we would have little occasion ever to find a statute unconstitutionally discriminatory. Virtually every discriminatory statute allocates benefits or burdens unequally; each can be viewed as conferring a benefit on one party and a detriment on the other, in either an absolute or relative sense. The determination of constitutionality does not depend upon whether one focuses upon the benefited or the burdened party. A discrimination claim, by its nature, requires a comparison of the two classifications, and it could always be said that there was no intent to impose a burden on one party, but rather the intent was to confer a benefit on the other. Consequently, it is irrelevant to the Commerce Clause inquiry that the motivation of the legislature was the desire to aid the makers of the locally produced beverage rather than to harm out-of-state producers.
We therefore conclude that the Hawaii liquor tax exemption for okolehao and pineapple wine violated the Commerce Clause because it had both the purpose and effect of discriminating in favor of local products.
> HH
The State argues in this Court that even if the tax exemption violates ordinary Commerce Clause principles, it is saved by the Twenty-first Amendment to the Constitution. Section 2 of that Amendment provides: “The transportation or importation into any State, Territory, or possession of the United States for delivery or use therein of intoxicating liquors, in violation of the laws thereof, is hereby prohibited.”
Despite broad language in some of the opinions of this Court written shortly after ratification of the Amendment, more recently we have recognized the obscurity of the legislative history of § 2. See California Retail Liquor Dealers Assn. v. Midcal Aluminum, Inc., 445 U. S. 97, 107, n. 10 (1980). No clear consensus concerning the meaning of the provision is apparent. Indeed, Senator Blaine, the Senate sponsor of the Amendment resolution, appears to have espoused varying interpretations. In reporting the view of the Senate Judiciary Committee, he said that the purpose of §2 was “to restore to the States . . . absolute control in effect over interstate commerce affecting intoxicating liquors . . . 76 Cong. Rec. 4143 (1933). On the other hand, he also expressed a narrower view: “So to assure the so-called dry States against the importation of intoxicating liquor into those States, it is proposed to write permanently into the Constitution a prohibition along that line.” Id., at 4141.
It is by now clear that the Amendment did not entirely remove state regulation of alcoholic beverages from the ambit of the Commerce Clause. For example, in Hostetter v. Idlewild Bon Voyage Liquor Corp., 377 U. S. 324, 331-332 (1964), the Court stated:
“To draw a conclusion. . .that the Twenty-first Amendment has somehow operated to ‘repeal’ the Commerce Clause wherever regulation of intoxicating liquors is concerned would, however, be an absurd oversimplification.”
We also there observed that “[b]oth the Twenty-first Amendment and the Commerce Clause are parts of the same Constitution [and] each must be considered in light of the other and in the context of the issues and interests at stake in any concrete case.” Id., at 332. Similarly, in Midcal Aluminum, supra, at 109, the Court, noting that recent Twenty-first Amendment cases have emphasized federal interests to a greater degree than had earlier cases, described the mode of analysis to be employed as a “pragmatic effort to harmonize state and federal powers.” The question in this case is thus whether the principles underlying the Twenty-first Amendment are sufficiently implicated by the exemption for okolehao and pineapple wine to outweigh the Commerce Clause principles that would otherwise be offended. Or as we recently asked in a slightly different way, “whether the interests implicated by a state regulation are so closely related to the powers reserved by the Twenty-first Amendment that the regulation may prevail, notwithstanding that its requirements directly conflict with express federal policies.” Capital Cities Cable, Inc. v. Crisp, 467 U. S. 691, 714 (1984).
Approaching the case in this light, we are convinced that Hawaii’s discriminatory tax cannot stand. Doubts about the scope of the Amendment’s authorization notwithstanding, one thing is certain: The central purpose of the provision was not to empower States to favor local liquor industries by erecting barriers to competition. It is also beyond doubt that the Commerce Clause itself furthers strong federal interests in preventing economic Balkanization. South-Central Timber Development, Inc. v. Wunnicke, 467 U. S. 82 (1984); Hughes v. Oklahoma, 441 U. S. 322 (1979); Baldwin v. G. A. F. Seelig, Inc., 294 U. S. 511 (1935). State laws that constitute mere economic protectionism are therefore not entitled to the same deference as laws enacted to combat the perceived evils of an unrestricted traffic in liquor. Here, the State does not seek to justify its tax on the ground that it was designed to promote temperance or to carry out any other purpose of the Twenty-first Amendment, but instead acknowledges that the purpose was “to promote a local industry.” Brief for Appellee Dias 40. Consequently, because the tax violates a central tenet of the Commerce Clause but is not supported by any clear concern of the Twenty-first Amendment, we reject the State’s belated claim based on the Amendment.
V
The State further contends that even if the challenged tax is adjudged to have been unconstitutionally discriminatory and should not have been collected from the wholesalers as long as the exemptions for local products were in force, the wholesalers are not entitled to refunds since they did not bear the economic incidence of the tax but passed it on as a separate addition to the price that their customers were legally obligated to pay within a certain time. Relying on United States v. Jefferson Electric Mfg. Co., 291 U. S. 386 (1934), a case involving interpretation of a federal tax refund statute, the State asserts that only the parties bearing the economic incidence of the tax are constitutionally entitled to a refund of an illegal tax. It further asserts that the wholesalers, at least arguably, do not even bear the legal obligation for the tax and that they have shown no competitive injury from the alleged discrimination. The wholesalers assert, on the other hand, that they were liable to pay the tax whether or not their customers paid their bills on time and that if the tax was illegally discriminatory the Commerce Clause requires that the taxes collected be refunded to them. Their position is also that the discrimination has worked a competitive injury on their business that entitles them to a refund.
These refund issues, which are essentially issues of remedy for the imposition of a tax that unconstitutionally discriminated against interstate commerce, were not addressed by the state courts. Also, the federal constitutional issues involved may well be intertwined with, or their consideration obviated by, issues of state law. Also, resolution of those issues, if required at all, may necessitate more of a record than so far has been made in this case. We are reluctant, therefore, to address them in the first instance. Accordingly, we reverse the judgment of the Supreme Court of Hawaii and remand for further proceedings not inconsistent with this opinion.
So ordered.
Justice Brennan took no part in the consideration or decision of this case.
An exemption for okolehao that had been enacted in 1960 expired in 1965. 1960 Haw. Sess. Laws, ch. 26, § 1. During the pendency of this litigation, the Hawaii Legislature enacted a similar exemption for rum manufactured in the State for the period May 17, 1981, to June 30, 1986.
Two other taxpayers — Foremost-McKesson, Inc., and Paradise Beverages, Inc. — were appellants in the consolidated suit in the Hawaii Supreme Court. They did not appeal to this Court and thus are appellees here pursuant to our Rule 10.4. For the sake of clarity, both appellants and appellee wholesalers will be referred to collectively as “wholesalers.”
Bacchus Imports, Ltd., was the first of the wholesalers to protest the assessment. It sent a letter dated May 30, 1979, protesting the payment of taxes for the period December 1977 through May 1979. Appellee Paradise Beverages, Inc., protested on July 30, 1979, for the period June 1977 through July 1979; appellant Eagle Distributors, Inc., protested on August 31, 1979, taxes paid from August 1974 through July 1979; and, on September 6,1979, appellee Foremost-McKesson, Inc., protested taxes paid from August 1974 through August 1979. In re Bacchus Imports, Ltd., 65 Haw. 566, 570, n. 11, 656 P. 2d 724, 728, n. 11 (1982).
Article I, § 10, cl. 2, of the Constitution provides in part:
“No State shall, without the Consent of the Congress, lay any Imposts or Duties on Imports or Exports . . . .”
Article I, § 8, cl. 3, of the Constitution provides in part:
“The Congress shall have power . . . [t]o regulate Commerce with foreign Nations, and among the several States . . .
Eagle Distributors sought refund of $10,744,047, App. 7; Bacchus sought $75,060.22, id., at 13; Foremost-McKesson sought over $26 million, id., at 19; and Paradise sought $8,716,727.23, Record in No. 1862, p. 27.
The State also would have us avoid the merits by holding that the exemptions are severable and should not invalidate the entire tax. The argument was not presented to the Supreme Court of Hawaii and that court did not proceed on any such basis. Furthermore, the challenged exemptions have now expired and “severance” would not relieve the harm inflicted during the time the wholesalers’ imported products were taxed but locally produced products were not.
The State does not seriously defend the Hawaii Supreme Court’s conclusion that because there was no discrimination between in-state and out-of-state taxpayers there was no Commerce Clause violation. Our cases make clear that discrimination between in-state and out-of-state goods is as offensive to the Commerce Clause as discrimination between in-state and out-of-state taxpayers. Compare I. M. Darnell & Son Co. v. Memphis, 208 U. S. 113 (1908), with Maryland v. Louisiana, 451 U. S. 725 (1981).
The percentage of exempted liquor sales steadily increased from .2221% of total liquor sales in 1976 to .7739% in 1981. App. to Brief for Appellee Dias A-l.
The Hawaii Supreme Court’s assumption that okolehao and pineapple wine do not pose “a competitive threat” does not constitute a finding that there is no competition whatsoever between locally produced products and out-of-state products, nor do we understand the State to so argue.
Because of our disposition of the Commerce Clause issue, we need not address the wholesalers’ arguments based upon the Equal Protection Clause and the Import-Export Clause.
We note that the State expressly disclaimed any reliance upon the Twenty-first Amendment in the court below and did not cite it in its motion to dismiss or affirm. Apparently it was not until it prepared its brief on the merits in this Court that it became “clear” to the State that the Amendment saves the challenged tax. See Brief for Appellee Dias 36.
For example, in State Board of Equalization v. Young’s Market Co., 299 U. S. 59, 62 (1936), the Court stated:
“The plaintiffs ask us to limit this broad command. They request us to construe the Amendment as saying, in effect: The State may prohibit the importation of intoxicating liquors provided it prohibits the manufacture and sale within its borders; but if it permits such manufacture and sale, it must let imported liquors compete with the domestic on equal terms. To say that, would involve not a construction of the Amendment, but a rewriting of it.”
The Court went on to observe, however, that a high license fee for importation may “serve as an aid in policing the liquor traffic.” Id., at 63.
See also Mahoney v. Joseph Triner Corp., 304 U. S. 401, 403 (1938) (“since the adoption of the Twenty-first Amendment, the equal protection clause is not applicable to imported intoxicating liquor”). Cf. Craig v. Boren, 429 U. S. 190 (1976).
It may be, for example, that given an unconstitutional discrimination, a full refund is mandated by state law.
What follows is an opinion from the Supreme Court of the United States. Your task is to determine whether the decision of the court whose decision the Supreme Court reviewed was itself liberal or conservative. In the context of issues pertaining to criminal procedure, civil rights, First Amendment, due process, privacy, and attorneys, consider liberal to be pro-person accused or convicted of crime, or denied a jury trial, pro-civil liberties or civil rights claimant, especially those exercising less protected civil rights (e.g., homosexuality), pro-child or juvenile, pro-indigent pro-Indian, pro-affirmative action, pro-neutrality in establishment clause cases, pro-female in abortion, pro-underdog, anti-slavery, incorporation of foreign territories anti-government in the context of due process, except for takings clause cases where a pro-government, anti-owner vote is considered liberal except in criminal forfeiture cases or those where the taking is pro-business violation of due process by exercising jurisdiction over nonresident, pro-attorney or governmental official in non-liability cases, pro-accountability and/or anti-corruption in campaign spending pro-privacy vis-a-vis the 1st Amendment where the privacy invaded is that of mental incompetents, pro-disclosure in Freedom of Information Act issues except for employment and student records. In the context of issues pertaining to unions and economic activity, consider liberal to be pro-union except in union antitrust where liberal = pro-competition, pro-government, anti-business anti-employer, pro-competition, pro-injured person, pro-indigent, pro-small business vis-a-vis large business pro-state/anti-business in state tax cases, pro-debtor, pro-bankrupt, pro-Indian, pro-environmental protection, pro-economic underdog pro-consumer, pro-accountability in governmental corruption, pro-original grantee, purchaser, or occupant in state and territorial land claims anti-union member or employee vis-a-vis union, anti-union in union antitrust, anti-union in union or closed shop, pro-trial in arbitration. In the context of issues pertaining to judicial power, consider liberal to be pro-exercise of judicial power, pro-judicial "activism", pro-judicial review of administrative action. In the context of issues pertaining to federalism, consider liberal to be pro-federal power, pro-executive power in executive/congressional disputes, anti-state. In the context of issues pertaining to federal taxation, consider liberal to be pro-United States and conservative pro-taxpayer. In miscellaneous, consider conservative the incorporation of foreign territories and executive authority vis-a-vis congress or the states or judcial authority vis-a-vis state or federal legislative authority, and consider liberal legislative veto. The lower court's decision direction is unspecifiable if the manner in which the Supreme Court took jurisdiction is original or certification; or if the direction of the Supreme Court's decision is unspecifiable and the main issue pertains to private law or interstate relations