How can the state conjure such money from nothing? The answer is that Ms. Brewer and Arizona hospitals have cooked up a spending scheme to rip off national taxpayers to avoid even the $154 million the state would at first pay. The hospital lobby first floated this scheme in 2011 “for the specific purpose of generating matching federal Medicaid funds.”

Here’s how it works: Arizona will tax hospitals and insurers for the $154 million. Then it will return $154 million to the health industry via more Medicaid business that will cover the cost of the tax and then some. The money needs to make a round trip from providers to the state and back to providers to game that 67% federal matching rate. …

Some 49 state now use this trick of so-called provider taxes to goose federal spending, up from 21 in 2003. (Alaska is the exception.) But the practice is so abusive that even Mr. Obama proposed new limits in his last two budgets.

This subsidy honeypot can’t last forever, which is why other Governors are more skeptical about this Obama Medicaid windfall. When the money inevitably runs out, states will retain permanently larger obligations and lose budget autonomy for a generation or two as health care crowds out other priorities like education and roads.