Arizona Christian School Tuition Organization v. Winn, 131 S. Ct. 1436

Arizona provides dollar-for-dollar tax credits up to $500 per person and $1,000 per couple for contributions to STOs that fund private school scholarships, including religious schools.
Respondents, Arizona taxpayers, challenge § 43-1089 as violating the Establishment Clause, arguing state funds are used to support religion.
Initially, the district court dismissed under the Tax Injunction Act; the Ninth Circuit held standing under Flast and reached the merits; the Supreme Court granted certiorari.
The majority concludes taxpayers lack standing under Article III because they cannot show a particularized injury traceable to the government, and the Flast exception does not apply.
The decision treats tax credits as not extracting funds from the taxpayer’s treasury in the same way as direct expenditures, distinguishing tax expenditures from appropriations for standing purposes.
The Court reverses the Ninth Circuit, holding the plaintiffs lack jurisdiction to adjudicate the Establishment Clause claim.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Arizona taxpayers have standing to challenge STO tax credits under Flast	Winn argues Flast applies, giving standing to challenge tax-related Establishment Clause violations.	Arizona asserts Flast’s two-part nexus does not apply because funds aren’t extracted from taxpayers’ own pockets.	No standing; Flast does not validate taxpayer standing here.
Whether STO tax credits constitute an injury sufficient for standing	Taxpayers suffer injury when public resources support religion through tax credits.	Injury is too indirect and speculative; credits are private contributions and do not extract funds.	Injury not established; no standing on general taxpayer grounds.
Whether the Flast narrow exception applies to tax credits	Flast permits standing for taxes and spending to violate the Establishment Clause, including tax credits.	Flast is a narrow anomaly; does not apply to tax credits standing.	Flast exception not satisfied; no standing.
If standing exists, whether relief would be redressable and traceable to the government	Injunction against the tax credit would address the injury.	Any injury is speculative and not traceable to the government’s current action.	Redressability/causation not established; no standing.

Abington Township School District v. Schempp, 374 U.S. 203 (U.S. 1963) (standards for Establishment Clause standing when direct injury to children is claimed)
Texas Monthly, Inc. v. Bullock, 489 U.S. 1 (U.S. 1989) (standing where costs/benefits relate to religious affiliation)
Flast v. Cohen, 392 U.S. 83 (U.S. 1968) (narrow taxpayer-standing exception for Establishment Clause challenges to congressional spending)
Frothingham v. Mellon, 262 U.S. 447 (U.S. 1923) (taxpayer standing general rule; injury too remote and indeterminate)
Doremus v. Board of Ed. of Hawthorne, 342 U.S. 429 (U.S. 1952) (standing requires direct injury; mere taxpayer status insufficient)
DaimlerChrysler Corp. v. Cuno, 547 U.S. 332 (U.S. 2006) (tax subsidies and expenditures analyzed for injury and redressability)
Hibbs v. Winn, 542 U.S. 88 (U.S. 2004) (standing considerations in tax-related Establishment Clause challenges)
Mueller v. Allen, 463 U.S. 388 (U.S. 1983) (establishment challenge to state tax deduction for private-school expenses)
Walz v. Tax Comm’n of City of New York, 397 U.S. 664 (U.S. 1970) (standing in Establishment Clause challenges to tax exemptions)
Hunt v. McNair, 413 U.S. 734 (U.S. 1973) (standing to challenge tax-exempt subsidies to religious institutions)