Governors in five states say they oppose expanding theirMedicaid programs under President Barack Obama's health-careoverhaul, and another 26 haven't decided, an option created by aU.S. Supreme Court ruling that may prevent millions of low-incomeAmericans from obtaining insurance.

Governors of Florida, Louisiana, Iowa, South Carolina andMississippi object, saying they're concerned rising health-carecosts may force tax increases or cuts to services, even as thefederal government is promising to cover all the added Medicaidcosts in the first three years and 90 percent after that. Thefederal reimbursement is about 59 percent now, on average.

Most of the governors resisting the Medicaid expansion areRepublicans who objected to the health-care law as unconstitutionalor too costly. If all 31 states don't go along, as many as 11.4million Americans who would otherwise be eligible for expandedMedicaid may be left without the coverage that Obama and Congressintended to offer, according to the Urban Institute, aWashington-based research group.