HARRISBURG — Gov. Tom Corbett has won approval for elements of a federally-funded health care expansion his administration spent more than a year developing, but he is facing an uphill battle for a second term and some parts of the plan may not survive for long if Democrat Tom Wolf beats him in November’s election.

Following approval Thursday by the U.S. Department of Health and Human Services, the Corbett administration is now tasked with setting up a system for more than a half-million more low-income Pennsylvanians to get federally funded health insurance through a private insurer.

The system it creates will be distinct from the existing managed care system that serves many of Pennsylvania’s 2.2 million Medicaid enrollees through private insurers. The insurance plans under the new system will be different, and insurers that participate can impose premiums on enrollees who earn above the poverty level, about $11,670 a year for a single, childless adult.

Federal officials rejected the Republican governor’s bid to undo some Medicaid rules to give private insurers more control over coverage and enrollment. Still, advocates for the poor said Friday certain elements negotiated by the Corbett administration are punitive or complex.

But they are not necessarily permanent, some say.

“It would be very doable for another governor to come in and do something different because this is not that different from current Medicaid managed care and the feds would be fine and happy with that,” said Joan Alker, executive director of Georgetown University’s Center for Children and Families, who has closely followed states’ Medicaid expansion plans.

Sen. Vince Hughes, D-Philadelphia, noted the premium structure in the new Medicaid expansion plans would not take effect until 2016 and there would be time to make changes if Wolf becomes governor.

Wolf, who supported an immediate expansion of traditional Medicaid, is already critical of the Medicaid plan negotiated by the Corbett administration.

“Tom Wolf would move forward with traditional Medicaid expansion,” spokesman Jeffrey Sheridan said. “Governor Corbett’s plan creates unnecessary bureaucracy and threatens higher premiums for certain recipients and future benefit cuts.”

Enrollment in the plan, named Healthy Pennsylvania, begins Dec. 1 either through county welfare offices, a toll-free number or the state’s one-stop public benefits website, called Compass.