At the Cato blog, Andrew J. Coulson brings up something I was not aware of: The Arizona Supreme Court has bought into the idea that tax-credit voucher programs — that is, having corporations fund voucher programs, and then reimbursing them (in full or close to it) with tax credits — are legally different than traditional voucher programs (in which the government first collects tax money and then spends it). From the decision:

Petitioners argue that this tax credit channels public money to private and sectarian schools in violation of the state constitution. . . . As respondents note, however, no money ever enters the state’s control as a result of this tax credit. Nothing is deposited in the state treasury or other accounts under the management or possession of governmental agencies or public officials. Thus, under any common understanding of the words, we are not here dealing with “public money.”

If the Supreme Court buys this logic — which I suppose is sound on its face — it could lead to some very interesting programs. Any time it’s illegal for a government to fund something directly, it could simply make a dollar-for-dollar “tax credit” program for it, allowing sympathetic taxpayers to technically “donate” — but actually just redirect the taxes they’d otherwise have to pay — to the cause.