Republican Sens. John Thune, Lamar Alexander, and Orrin Hatch proposed a bill Tuesday to prevent the administration from exempting unions from the reinsurance tax required under Obamacare.

The White House is considering exempting certain self-insured, self-administered insurance plans from the reinsurance fee, an exemption that would include the plans commonly held by union members, known as Taft Hartley plans. Unions have asked to be exempted from the tax.

The reinsurance tax on individuals is meant to help insurance companies on the exchanges deal with potentially higher costs as a result of having to cover people with pre-existing conditions.

“Unions should not be granted a special exemption from Obamacare’s reinsurance tax just because the president fears further union backlash on his signature law,” Thune said in a statement. “These unions agreed to pay this tax when they endorsed Obamacare, but now that they are finding out what the law means for them and their plans, they want out. Rather than granting special back room deals to political allies, the administration should support fairness for all by permanently delaying the law for every American.”

Alexander, in a statement, described the reinsurance tax as another “job-killing” tax, blasting the White House.

“The administration should be embarrassed that it would consider exempting their union cronies without providing similar relief to our nation’s employers and faith-based and charitable organizations,” he said.

“The Obama Administration can’t just circumvent Congress whenever it wants to curry favor with its political allies,” added Hatch, calling the potential exemption a “political payback by the Administration to its union friends for backing this disastrous law.”

Eight other Republican senators have also signed onto the bill: Oklahoma Sen. Jim Inhofe, Louisiana Sen. David Vitter, Wyoming Sen. Mike Enzi, Wisconsin Sen. Ron Johnson, Wyoming Sen. John Barrasso, South Carolina Sen. Tim Scott, Georgia Sen. Saxby Chambliss, and Oklahoma Sen. Tom Coburn.