Ar.Christ.Sch.Tuition v. Winn, 131 S.Ct. 1436 (2011)

The State of Arizona established a tax credit to any taxpayer who elected to contribute to a school tuition organization of their choice and recognized and approved by the state. The credit applied to secular and religious schools and a taxpayer could decline to seek the credit.  Disgruntled taxpayers alleged an Establishment Clause violation and the 9th Circuit agreed.
The Supreme Court reversed the 9th Circuit (again) and held the state extracted no money from its citizenry and the deduction was voluntary.
In an easy reversal of the 9th Circuit, the Court held the taxpayers who objected to this statute lacked standing to initiate a challenge.  Taxpayers suits have been repeatedly denied on grounds a general objection to tax policy is a legislative issue, not judicial; U.S. Const., Article III.
The Supreme Court again reminds federal appellate courts of the tripartite branch of government and unless the state explicitly applies taxpayer funds to a religious entity the legislative decision is unassailable in court.