The other Paul Ryan plan: $800B in Medicaid cuts

Under current law, the federal Medicaid share is pegged to program enrollment, not population growth, said John Holahan, director of the Health Policy Center at the nonpartisan Urban Institute. That means federal funding increases when the Medicaid rolls swell. But under Ryan's plan, "there are no provisions to automatically deal with recessions," said Holahan. "The demand for Medicaid goes up at the same time state revenue is going down."

—Would low-income and disabled people still have a legal right to coverage?

Converting Medicaid into a block grant would end the current right to coverage under federal law, and it remains unclear what rights could be preserved. Most analysts say states would insist on the flexibility to reduce their Medicaid rolls. The Urban Institute estimates that between 14 million and 27 million people would lose coverage because of Ryan's spending restrictions.

—What sorts of safeguards would remain in place for seniors in need of nursing home care?

Although frail elderly people must spend down most of their savings before they can qualify for Medicaid, a federal law shields spouses from becoming impoverished. It's unclear what would take its place.

Supporters of state control say governors and legislatures are closer to the people and would not run roughshod over their own constituents.

Back in Ryan's state, the jury is still out.

Medicaid covers nearly 1 in 5 Wisconsin residents, and hospitals have a major stake in the outcome. But Joanne Alig, senior vice president for policy with the Wisconsin Hospital Association, says they would need to know more about the plan to reach conclusions.

"While I think we are supportive of looking at alternatives to the Medicaid status quo, the devil's in the details," she said.