President Obama's Affordable Care Act could face challenges from GOP governors rejecting state-run health insurance exchanges. (Creative Commons)

With Republicans now controlling 30 of the nation’s 50 governors’ seats, Obama could face growing GOP efforts to undermine key legislation during the next four years, with the Affordable Care Act being at the top of the agenda.

The battle is expected to escalate after president proposed new rules on Tuesday that would require insurance companies to cover people with pre-existing conditions.

Although Obamacare survived efforts to strike it down, some observers suggest GOP governors may have another strategy to oppose the law: render it ineffective.

From The Washington Post:

Republican governors are trying to accomplish this by turning down the chance to run state-based exchanges. Remember that under the health law, state governments will set up on-line insurance marketplaces so that those without insurance can easily compare and purchase the private-market package best for them. The law did allow for states to opt out, in which case the federal government would do it for them ... The key, however, is that they simply don’t want this policy to work, so they’re simply refusing to implement it.

The exchanges would allow consumers and small businesses to shop around for insurance plans, and help low-income families at or below 133 percent of the federal poverty line to enroll in Medicaid. Under Obamacare, the federal government would pay 100 percent of costs for the first three years starting in 2014, before more of the cost gradually shifts toward the states.

Obama’s re-election ensures that conservatives against the Affordable Care Act will not get their wish of having the law appealed. But GOP governors are still facing stepped up pressure from the party’s right wing to reject the expansion of Medicaid and the state-run insurance exchange requirement.

Americans for Prosperity, a conservative advocacy group linked to the billionaire Koch brothers, issued a statement to governors urging them to push back against the law.

“States can and do have the power to reject federal attempts to compel their action," AFP State Policy Manager Nicole Kaeding said in the statement. "Governors should use that power to tell the federal government no. By creating an exchange, states will serve as de-facto administrators of the federal government implementing its rules, regulations and mandates.”

In a Nov. 18 opinion piece published in USA Today, Texas Gov. Rick Perry, one of the governors against the health care law, said the exchanges “represent nothing more than another federal power grab in the guise of a supposedly free market.”

Perry said in a video statement, “I will not be part of socializing health care and bankrupting my state in direct contradiction to our constitution and our founding principles of limited government.”

Texas has the highest proportion of uninsured residents in the country at 25 percent, while four of the top 10 most uninsured metropolitan areas in the country are based in the Lone Star state.

The deadline for states to set up health insurance exchanges now set for Dec. 14. Other Republican governors who have taken a stance against operating state-run health markets include Bobby Jindal of Louisiana, John Kasich of Ohio and Scott Walker of Wisconsin.

Kasich hinted that Ohio will reject the mandate of operating a state-based exchange, leaving the responsibility of establishing an exchange up to the federal government.

"At this point, based on the information we have, states do not have the flexibility to build and manage exchanges in ways that respond to unique needs of their citizens or markets," Kasich wrote in a letter to the Obama administration. "Regardless of who runs the exchange, the end product is the same."

Eight of the 10 states with the highest percentage of uninsured have a Republican governor in power.

Read more Neon Tommy stories on Obamacare here.

Reach Senior Staff Reporter Danny Lee here; follow him here.