The Establishment Clause of the First Amendment prohibits a State from subsidizing religious education, whether it does so directly or indirectly. In my view, this principle of neutrality forbids not only the tax benefits struck down in Committee for Public Education v. Nyquist, 413 U. S. 756 (1973), but any tax benefit, including the tax deduction at issue here, which subsidizes tuition payments to sectarian schools. I also believe that the Establishment Clause prohibits the tax deductions that Minnesota authorizes for the cost of books and other instructional materials used for sectarian purposes.
I
The majority today does not question the continuing vitality of this Court’s decision in Nyquist. That decision established that a State may not support religious education either through direct grants to parochial schools or through financial aid to parents of parochial school students. Id., at 780, 785-786. Nyquist also established that financial aid to parents of students attending parochial schools is no more permissible if it is provided in the form of a tax credit than if provided in the form of cash payments. Id., at 789-791; see ante, at 396-397, n. 6. Notwithstanding these accepted prin*405ciples, the Court today upholds a statute that provides a tax deduction for the tuition charged by religious schools. The Court concludes that the Minnesota statute is “vitally different” from the New York statute at issue in Nyquist. Ante, at 398. As demonstrated below, there is no significant difference between the two schemes. The Minnesota tax statute violates the Establishment Clause for precisely the same reason as the statute struck down in Nyquist: it has a direct and immediate effect of advancing religion.
A
In calculating their net income for state income tax purposes, Minnesota residents are permitted to deduct the cost of their children’s tuition, subject to a ceiling of $500 or $700 per child. By taking this deduction, a taxpayer reduces his tax bill by a sum equal to the amount of tuition multiplied by his rate of tax. Although this tax benefit is available to any parents whose children attend schools which charge tuition, the vast majority of the taxpayers who are eligible to receive the benefit are parents whose children attend religious schools. In the 1978-1979 school year, 90,000 students were enrolled in nonpublic schools charging tuition; over 95% of those students attended sectarian schools. Although the statute also allows a deduction for the tuition expenses of children attending public schools, Minnesota public schools are generally prohibited by law from charging tuition. Minn. Stat. §120.06 (1982). Public schools may assess tuition charges only for students accepted from outside the district. § 123.39, subd. 5. In the 1978-1979 school year, only 79 public school students fell into this category. The parents of the remaining 815,000 students who attended public schools were ineligible to receive this tax benefit.
Like the law involved in Nyquist, the Minnesota law can be said to serve a secular purpose: promoting pluralism and diversity among the State’s public and nonpublic schools. But the Establishment Clause requires more than that legislation have a secular purpose. Nyquist, 413 U. S., at 773. “[T]he *406propriety of a legislature’s purposes may not immunize from further scrutiny a law which . . . has a primary effect that advances religion.” Id., at 774.1 Moreover, even if one “‘primary’ effect [is] to promote some legitimate end under the State’s police power,” the legislation is not “immune from further examination to ascertain whether it also has the direct and immediate effect of advancing religion.” Id., at 783-784, n. 39. See, e. g., Wolman v. Walter, 433 U. S. 229, 248-254 (1977); Meek v. Pittenger, 421 U. S. 349, 364-366 (1975).
As we recognized in Nyquist, direct government subsidization of parochial school tuition is impermissible because “the effect of the aid is unmistakably to provide desired financial support for nonpublic, sectarian institutions.” 413 U. S., at 783. “[A]id to the educational function of [parochial] schools . . . necessarily results in aid to the sectarian school enterprise as a whole” because “[t]he very purpose of many of those schools is to provide an integrated secular and religious education.” Meek v. Pittenger, supra, at 366. For this reason, aid to sectarian schools must be restricted to ensure that it may be not used to further the religious mission of those schools. See, e. g., Wolman v. Walter, supra, at 250-251. While “services such as police and fire protection, sewage disposal, highways, and sidewalks,” may be provided to parochial schools in common with other institutions, because this type of assistance is clearly “‘marked off from the religious function’” of those schools, Nyquist, supra, at 781-782, quoting Everson v. Board of Education, 330 U. S. 1, 18 (1947), unrestricted financial assistance, such as grants for the maintenance and construction of parochial schools, may not be *407provided. Nyquist, 413 U. S., at 774-780. “In the absence of an effective means of guaranteeing that the state aid derived from public funds will be used exclusively for secular, neutral, and nonideological purposes, it is clear from our cases that direct aid in whatever form is invalid.” Id., at 780.
Indirect assistance in the form of financial aid to parents for tuition payments is similarly impermissible because it is not “subject to . . . restrictions” which “‘guarantee the separation between secular and religious educational functions and . . . ensure that State financial aid supports only the former.’” Id., at 783, quoting Lemon v. Kurtzman, 403 U. S. 602, 613 (1971). By ensuring that parents will be reimbursed for tuition payments they make, the Minnesota statute requires that taxpayers in general pay for the cost of parochial education and extends a financial “incentive to parents to send their children to sectarian schools.” Nyquist, 413 U. S., at 786. As was true of the law struck down in Nyquist:
“[I]t is precisely the function of [Minnesota’s] law to provide assistance to private schools, the great majority of which are sectarian. By reimbursing parents for a portion of their tuition bill, the State seeks to relieve their financial burdens sufficiently to assure that they continue to have the option to send their children to religion-oriented schools. And while the other purposes for that aid — to perpetuate a pluralistic educational environment and to protect the fiscal integrity of overburdened public schools — are certainly unexceptionable, the effect of the aid is unmistakably to provide desired financial support for nonpublic, sectarian institutions.” Id., at 783
That parents receive a reduction of their tax liability, rather than a direct reimbursement, is of no greater significance here than it was in Nyquist. “[F]or purposes of determining whether such aid has the effect of advancing religion,” *408it makes no difference whether the qualifying “parent receives an actual cash payment [or] is allowed to reduce . . . the sum he would otherwise be obliged to pay over to the State.” Id., at 790-791. It is equally irrelevant whether a reduction in taxes takes the form of a tax “credit,” a tax “modification,” or a tax “deduction.” Id., at 789-790. What is of controlling significance is not the form but the “substantive impact” of the financial aid. Id., at 786. “[IJnsofar as such benefits render assistance to parents who send their children to sectarian schools, their purpose and inevitable effect are to aid and advance those religious institutions.” Id., at 793 (emphasis added).
B
The majority attempts to distinguish Nyquist by pointing to two differences between the Minnesota tuition-assistance program and the program struck down in Nyquist. Neither of these distinctions can withstand scrutiny.
1
The majority first attempts to distinguish Nyquist on the ground that Minnesota makes all parents eligible to deduct up to $500 or $700 for each dependent, whereas the New York law allowed a deduction only for parents whose children attended nonpublic schools. Although Minnesota taxpayers who send their children to local public schools may not deduct tuition expenses because they incur none, they may deduct other expenses, such as the cost of gym clothes, pencils, and notebooks, which are shared by all parents of school-age children. This, in the majority’s view, distinguishes the Minnesota scheme from the law at issue in Nyquist.
That the Minnesota statute makes some small benefit available to all parents cannot alter the fact that the most substantial benefit provided by the statute is available only to those parents who send their children to schools that charge tuition. It is simply undeniable that the single largest expense that may be deducted under the Minnesota statute is tuition. The statute is little more than a subsidy of tuition mas*409querading as a subsidy of general educational expenses. The other deductible expenses are de minimis in comparison to tuition expenses.
Contrary to the majority’s suggestion, ante, at 401, the bulk of the tax benefits afforded by the Minnesota scheme are enjoyed by parents of parochial school children not because parents of public school children fail to claim deductions to which they are entitled, but because the latter are simply unable to claim the largest tax deduction that Minnesota authorizes.2 Fewer than 100 of more than 900,000 school-age children in Minnesota attend public schools that charge a general tuition. Of the total number of taxpayers who are eligible for the tuition deduction, approximately 96% send their children to religious schools.3 Parents who send their children to free public schools are simply ineligible to obtain the full benefit of the deduction except in the unlikely event that they buy $700 worth of pencils, notebooks, and bus rides for their school-age children. Yet parents who pay at least $700 in tuition to nonpublic, sectarian schools can claim the full deduction even if they incur no other educational expenses.
That this deduction has a primary effect of promoting religion can easily be determined without any resort to the type of “statistical evidence” that the majority fears would lead to constitutional uncertainty. Ibid. The only factual inquiry necessary is the same as that employed in Nyquist *410and Sloan v. Lemon, 413 U. S. 825 (1973): whether the deduction permitted for tuition expenses primarily benefits those who send their children to religious schools. In Nyquist we unequivocally rejected any suggestion that, in determining the effect of a tax statute, this Court should look exclusively to what the statute on its face purports to do and ignore the actual operation of the challenged provision. In determining the effect of the New York statute, we emphasized that “virtually all” of the schools receiving direct grants for maintenance and repair were Roman Catholic schools, 413 U. S., at 774, that reimbursements were given to parents “who send their children to nonpublic schools, the bulk of which is concededly sectarian in orientation,” id., at 780, that “it is precisely the function of New York’s law to provide assistance to private schools, the great majority of which are sectarian,” id., at 783, and that “tax reductions authorized by this law flow primarily to the parents of children attending sectarian, nonpublic schools.” Id., at 794. Similarly, in Sloan v. Lemon, supra, at 830, we considered important to our “consider[ation of] the new law’s effect. . . [that] ‘more than 90% of the children attending nonpublic schools in the Commonwealth of Pennsylvania are enrolled in schools that are controlled by religious organizations or that have the purpose of propagating and promoting religious faith.’”4
*411In this case, it is undisputed that well over 90% of the children attending tuition-charging schools in Minnesota are enrolled in sectarian schools. History and experience likewise instruct us that any generally available financial assistance for elementary and secondary school tuition expenses mainly will further religious education because the majority of the schools which charge tuition are sectarian. Cf. Nyquist, 413 U. S., at 785; Lemon v. Kurtzman, 403 U. S., at 628-630 (Douglas, J., concurring). Because Minnesota, like every other State, is committed to providing free public education, tax assistance for tuition payments inevitably redounds to the benefit of nonpublic, sectarian schools and parents who send their children to those schools.
2
The majority also asserts that the Minnesota statute is distinguishable from the statute struck down in Nyquist in another respect: the tax benefit available under Minnesota law is a “genuine tax deduction,” whereas the New York law provided a benefit which, while nominally a deduction, also had features of a “tax credit.” Ante, at 396, and n. 6. Under the Minnesota law, the amount of the tax benefit varies directly with the amount of the expenditure. Under the New York law, the amount of deduction was not dependent upon the amount actually paid for tuition but was a predetermined amount which depended on the tax bracket of each taxpayer. The deduction was designed to yield roughly the same amount of tax “forgiveness” for each taxpayer.
This is a distinction without a difference. Our prior decisions have rejected the relevance of the majority’s formalistic distinction between tax deductions and the tax benefit at issue in Nyquist. See Byrne v. Public Funds for Public Schools, 442 U. S. 907 (1979), summarily aff’g 590 F. 2d 514 (CA3); Grit v. Wolman, 413 U. S. 901 (1973), summarily aff’g Kosydar v. Wolman, 353 F. Supp. 744 (SD Ohio 1972).5 *412The deduction afforded by Minnesota law was “designed to yield a [tax benefit] in exchange for performing a specific act which the State desires to encourage.” Nyquist, supra, at 789. Like the tax benefit held impermissible in Nyquist, the tax deduction at issue here concededly was designed to “en-courag[e] desirable expenditures for educational purposes.” Ante, at 396. Of equal importance, as the majority also concedes, the “economic consequenc[e]” of these programs is the same, ante, at 397, n. 6, for in each case the “financial assistance provided to parents ultimately has an economic effect comparable to that of aid given directly to the schools.” Ante, at 399. See Walz v. Tax Comm’n, 397 U. S. 664, 699 (1970) (opinion of Harlan, J.). It was precisely the substantive impact of the financial support, and not its particular form, that rendered the programs in Nyquist and Sloan *413v. Lemon unconstitutional. See Nyquist, supra, at 790-791, 794; Sloan v. Lemon, 413 U. S., at 832.
C
The majority incorrectly asserts that Minnesota’s tax deduction for tuition expenses “bears less resemblance to the arrangement struck down in Nyquist than it does to assistance programs upheld in our prior decisions and those discussed with approval in Nyquist.” Ante, at 394. One might as well say that a tangerine bears less resemblance to an orange than to an apple. The two cases relied on by the majority, Board of Education v. Allen, 392 U. S. 236 (1968), and Everson v. Board of Education, 330 U. S. 1 (1947), are inapposite today for precisely the same reasons that they were inapposite in Nyquist.
We distinguished these cases in Nyquist, supra, at 781-782, and again in Sloan v. Lemon, supra, at 832. Financial assistance for tuition payments has a consequence that
“is quite unlike the sort of ‘indirect’ and ‘incidental’ benefits that flowed to sectarian schools from programs aiding all parents by supplying bus transportation and secular textbooks for their children. Such benefits were carefully restricted to the purely secular side of church-affiliated institutions and provided no special aid for those who had chosen to support religious schools. Yet such aid approached the ‘verge’ of the constitutionally impermissible.” Sloan v. Lemon, supra, at 832 (latter emphasis added).
As previously noted, supra, at 409, the Minnesota tuition tax deduction is not available to all parents, but only to parents whose children attend schools that charge tuition, which are comprised almost entirely of sectarian schools. More importantly, the assistance that flows to parochial schools as a result of the tax benefit is not restricted, and cannot be restricted, to the secular functions of those schools.
*414In my view, Minnesota’s tax deduction for the cost of textbooks and other instructional materials is also constitutionally infirm. The majority is simply mistaken in concluding that a tax deduction, unlike a tax credit or a direct grant to parents, promotes religious education in a manner that is only “attenuated.” Ante, at 399, 400. A tax deduction has a primary effect that advances religion if it is provided to offset expenditures which are not restricted to the secular activities of parochial schools.
The instructional materials which are subsidized by the Minnesota tax deduction plainly may be used to inculcate religious values and belief. In Meek v. Pittenger, 421 U. S., at 366, we held that even the use of “wholly neutral, secular instructional material and equipment” by church-related schools contributes to religious instruction because “‘[t]he secular education those schools provide goes hand in hand with the religious mission that is the only reason for the schools’ existence.’” In Wolman v. Walter, 433 U. S., at 249-250, we concluded that precisely the same impermissible effect results when the instructional materials are loaned to the pupil or his parent, rather than directly to the schools. We stated that “it would exalt form over substance if this distinction were found to justify a result different from that in Meek.” Id., at 250. It follows that a tax deduction to offset the cost of purchasing instructional materials for use in sectarian schools, like a loan of such materials to parents, “necessarily results in aid to the sectarian school enterprise as a whole” and is therefore a “substantial advancement of religious activity” that “constitutes an impermissible establishment of religion.” Meek v. Pittenger, supra, at 366.
There is no reason to treat Minnesota’s tax deduction for textbooks any differently. Secular textbooks, like other secular instructional materials, contribute to the religious mission of the parochial schools that use those books. Although this Court upheld the loan of secular textbooks to religious *415schools in Board of Education v. Allen, supra, the Court believed at that time that it lacked sufficient experience to determine “based solely on judicial notice” that “the processes of secular and religious training are so intertwined that secular textbooks furnished to students by the public [will always be] instrumental in the teaching of religion.” 392 U. S., at 248. This basis for distinguishing secular instructional materials and secular textbooks is simply untenable, and is inconsistent with many of our more recent decisions concerning state aid to parochial schools. See Wolman v. Walter, 433 U. S., at 257-258 (Marshall, J., concurring in part and dissenting in part); id., at 264-266 (Stevens, J., concurring in part and dissenting in part); Meek v. Pittenger, supra, at 378 (Brennan, J., concurring in part and dissenting in part).
In any event, the Court’s assumption in Allen that the textbooks at issue there might be used only for secular education was based on the fact that those very books had been chosen by the State for use in the public schools. 392 U. S., at 244-245. In contrast, the Minnesota statute does not limit the tax deduction to those books which the State has approved for use in public schools. Rather, it permits a deduction for books that are chosen by the parochial schools themselves. Indeed, under the Minnesota statutory scheme, textbooks chosen by parochial schools but not used by public schools are likely to be precisely the ones purchased by parents for their children’s use. Like the law upheld in Board of Education v. Allen, supra, Minn. Stat. §§ 123.932 and 123.933 (1982) authorize the State Board of Education to provide textbooks used in public schools to nonpublic school students. Parents have little reason to purchase textbooks that can be borrowed under this provision.6
*416H-I I — i t — i
There can be little doubt that the State of Minnesota intended to provide, and has provided, “[substantial aid to the educational function of [church-related] schools,” and that the tax deduction for tuition and other educational expenses “necessarily results in aid to the sectarian school enterprise as a whole.” Meek v. Pittenger, supra, at 366. It is beside the point that the State may have legitimate secular reasons for providing such aid. In focusing upon the contributions made by church-related schools, the majority has lost sight of the issue before us in this case.
“The sole question is whether state aid to these schools can be squared with the dictates of the Religion Clauses. Under our system the choice has been made that government is to be entirely excluded from the area of religious instruction .... The Constitution decrees that religion must be a private matter for the individual, the family, and the institutions of private choice, and that while some involvement and entanglement are inevitable, lines must be drawn.” Lemon v. Kurtzman, 403 U. S., at 625.
In my view, the lines drawn in Nyquist were drawn on a reasoned basis with appropriate regard for the principles of neutrality embodied by the Establishment Clause. I do not believe that the same can be said of the lines drawn by the majority today. For the first time, the Court has upheld financial support for religious schools without any reason at all to assume that the support will be restricted to the secular functions of those schools and will not be used to support reli*417gious instruction. This result is flatly at odds with the fundamental principle that a State may provide no financial support whatsoever to promote religion. As the Court stated in Everson, 330 U. S., at 16, and has often repeated, see, e. g., Meek v. Pittenger, 421 U. S., at 359; Nyquist, 413 U. S., at 780:
“No tax in any amount, large or small, can be levied to support any religious activities or institutions, whatever they may be called, or whatever form they may adopt to teach or practice religion.”
I dissent.
As we noted in Nyquist, it is “firmly established” that a statute may impermissibly advance religion “even though it does not aid one religion more than another but merely benefits all religions alike.” 413 U. S., at 771. See, e. g., Wolman v. Walter, 433 U. S. 229, 248-254 (1977); Meek v. Pittenger, 421 U. S. 349, 364-366 (1975).
Even if the Minnesota statute allowed parents of public school students to deduct expenses that were likely to be equivalent to the tuition expenses of private school students, it would still be unconstitutional. Insofar as the Minnesota statute provides a deduction for parochial school tuition, it provides a benefit to parochial schools that furthers the religious mission of those schools. Nyquist makes clear that the State may not provide any financial assistance to parochial schools unless that assistance is limited to secular uses. 413 U. S., at 780-785.
Indeed, in this respect the Minnesota statute has an even greater tendency to promote religious education than the New York statute struck down in Nyquist, since the percentage of private schools that are nonsectarian is far greater in New York than in Minnesota.
Similarly, in Meek v. Pittenger, 421 U. S., at 363, we held that “the direct loan of instructional material and equipment has the unconstitutional primary effect of advancing religion because of the predominantly religious character of the schools benefiting from the Act.” See id., at 366. We relied on a finding that “of the 1,320 nonpublic schools in Pennsylvania that . . . qualify for aid under Act 195, more than 75% are church-related or religiously affiliated educational institutions.” Id., at 364. This could not possibly have been ascertained from the text of the facially neutral statute, but could only be determined on the basis of an “empirical inquiry.” And in Wolman v. Walter, 433 U. S., at 234, the Court relied on a stipulation that “during the 1974-1975 school year there were 720 chartered nonpublic schools in Ohio. Of these, all but 29 were sectarian. More than 96% of the nonpublic enrollment attended sectarian schools, and more than 92% attended Catholic schools.”
In Byrne v. Public Funds for Public Schools, we summarily affirmed a decision striking down a program of tax deductions. The amount of de*412duction was fixed at $1,000 for each dependent attending a tuition-charging nonpublic school. This decision makes clear that the constitutionality of a tax benefit does not turn on whether the benefit is in the form of a deduction from gross income or a tax “credit.”
In Grit v. Wolman, we summarily affirmed a decision invalidating a system of tax credits for nonpublic school parents in which the amount of the credit depended on the amount of tuition paid. This decision demonstrates that it is irrelevant whether the amount of a tax benefit is proportionate to the amount of tuition paid or is simply an arbitrary sum. The Court’s affirmance of the result in each of these cases was a “decision on the merits, entitled to precedential weight.” Meek v. Pittenger, supra, at 366-367, n. 16.
The deduction at issue in this case does differ from the tax benefits in Nyquist and our other prior cases in one respect: by its very nature the deduction embodies an inherent limit on the extent to which a State may subsidize religious education. Unlike a tax credit, which may wholly subsidize the cost of religious education if the size of the credit is sufficiently large, or a tax deduction of an arbitrary sum, a deduction of tuition payments from adjusted gross income can never “provide a basis for . . . complete subsidization of. . . religious schools.” Nyquist, 413 U. S., at 782, n. 38 (emphasis in original). See also id., at 779, 787, n. 44. Nyquist made clear, however, that absolutely no subsidization is permissible unless it is restricted to the purely secular functions of those schools. See, e. g., id., at 777-779, 787-788.
For similar reasons, I would hold that the deduction for transportation expenses is constitutional only insofar as it relates to the costs of traveling between home and school. See Wolman v. Walter, 433 U. S., at 252-255 (reimbursement of nonpublic schools for field trip transportation impermis-*416sibly fosters religion because the nonpublic schools control the timing, frequency, and destination of the trips, which, for sectarian schools, are an integral part of the sectarian education). I would therefore reverse the judgment of the Court of Appeals and remand for a determination whether the insignificant deductions that remain — e. g., deductions for transportation between home and school and for pencils and notebooks — are sever-able from the other deductions.