Snyder said that in Michigan, the expansion would provide coverage for about 500,000 uninsured residents, mostly at federal expense, and save state taxpayers $1.2 billion through 2020. Many states now help hospitals cover some of the cost of treating those without insurance.
"This is a federal program that we would not have necessarily created for Michigan," he said Wednesday, but "this is saving money and improving lives."
Governors have been under immense pressure to opt in from hospital and medical associations, as well as advocates for the poor.
In explaining their decisions, Kasich, Brewer and others have said rejecting an expansion would mean their taxpayers would subsidize care for those in other states, while receiving no benefits themselves. In Ohio, that would be an estimated $2.4 billion over two years, Kasich said Monday.
"Ohio taxpayer dollars are coming back to Ohio to support a significant need we have," he said.
But governors elsewhere said they fear the states would be saddled with huge costs if the federal government later reneged on its commitment.
"The federal government, because of their budget problems, starts cutting back and...then you've just bought into something of a lead sinker," said Iowa Gov. Terry Branstad, among the skeptics. He has asked federal officials to allow his state to craft its own plan for low-income residents.
Virginia Gov. Bob McDonnell has also questioned the terms, saying he didn't "believe the federal government can possibly deliver its commitment to fully fund the program."
About half the states are preparing to participate in another part of the federal health plan —setting up an online marketplace, either by themselves or in partnership with Washington, where middle-class residents can shop for subsidized private insurance. This group includes a half dozen GOP-governed states. Under the new system, the federal government will set up the online marketplaces, or exchanges, for states that decline to do so. The new exchanges are scheduled to go into operation in October, with insurance coverage beginning in January 2014.
Scott Bauer in Madison, Wis., David Eggert in Lansing, Mich., and Catherine Lucey in Des Moines contributed.
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