MADISON, Wis. — A federal judge will hear arguments this week on whether to toss a U.S. senator’s lawsuit challenging rules that force congressional members and their staffs to obtain government-subsidized health insurance through small business exchanges.

Republican Sen. Ron Johnson of Wisconsin contends that senators, representatives and their employees aren’t eligible for the exchanges under the federal health care law because they work for a government that employs millions. He also argues that premium subsidies that congressional members and staffers receive will foster resentment among his constituents.

Republicans have spent years railing against President Barack Obama’s health care reform law, known as the Affordable Care Act. Johnson isn’t attacking the act itself, focusing instead on rules imposing the act on Congress. But he’s using the lawsuit as a mechanism to complain more broadly about what he sees as Obama unilaterally rewriting the act.

“This lawsuit offers a landmark opportunity to re-establish the balance between the executive and legislative branches of government,” Johnson said in a statement last month.

Government attorneys have asked U.S. District Judge William Griesbach to throw the case out of court. They argue Johnson hasn’t shown how the rules hurt him or his staff.

Griesbach, who was appointed by former President George W. Bush, has scheduled a hearing today in Green Bay to consider dismissing the lawsuit.