The Court's decision in Winn (Arizona school-choice case)

The Supreme Court's (5-4) decision in Winn is available here.  (Thanks to Howard Bashman for the link.)  I've read the decision quickly, and want to do so again, but the bottom line seems clear:  The Ninth Circuit's decision, which badly misapplied Zelman, is reversed, on standing grounds.  Because the tax-credit mechanism is one that involves not government expenditures (of the kind that worried James Madison in his Memorial and Remonstrance), but instead allows people to keep, and direct, their own money, the Flast exception to the no-taxpayer-standing rule does not apply.  

I'm torn:  I think Flast was probably a mistake, because I don't think (with all due respect!) that there's anything about the injury to a taxpayer who objects to public funds being spent on (say) a school-voucher program that distinguishes it, constitutionally, from the injury to a taxpayer who objects to public funds being spent on (say) a bridge in Alaska.  (I argued, in this short paper, that the Establishment Clause does protect "conscience", but not in the way that the Flast exception presumes.)  At the same time, I would have liked a majority opinion clearly rejecting, on the merits, the Establishment Clause challenge to the Arizona program.