A panel of federal court judges has rejected yet another conservative legal attack on President Obama’s signature health-care reform law, while the U.S. Supreme Court considers the fate of health insurance subsidies for millions of Americans who purchased policies through state-based exchanges.

The U.S. Court of Appeals for the Seventh Circuit unanimously rejected claims brought by Wisconsin Republican Sen. Ron Johnson that challenged the federal government’s ability to offer subsidies to members of Congress and their staff for health insurance under the Affordable Care Act.

The federal Office of Personnel Management in 2013 established regulations for how members of Congress and their staff members could obtain insurance coverage under the ACA. Under those rules, congressional employees must get their coverage through an insurance marketplace set up for small businesses in the Washington, D.C., area.

Congressional staff who are not considered part of the official office receive their insurance as an employee benefit, as those staff members had in the past. Johnson’s lawsuit claimed that those rules create a loophole for members of Congress to sidestep Obamacare provisions on providing insurance to their employees.

Johnson sued to keep himself and his staff on the exchanges, arguing he would suffer “reputational and electoral injury” that many of his constituents believe to be illegal.

A lower court dismissed Johnson’s lawsuit in July, ruling the senator and his aide didn’t have standing to bring the case because they had not been injured by the health-care law.

Tuesday’s ruling from the Seventh Circuit affirms that lower court’s ruling.

“Respectfully, we do not see how Senator Johnson’s reputation could be sullied or his electability diminished by being offered, against his will, a benefit that he then decided to refuse,” Judge Joel Flaum wrote for the panel of Seventh Circuit judges. “He could not be accused of participating in an illegal scheme if he declined to participate.”

Johnson criticized the ruling in a statement.

“For the second time, my attempt to restore the constitutional balance between the executive and legislative co-equal branches of government has been stymied by the courts,” Johnson said. “With this decision today, another executive action by the administration will go unchallenged, all based on the legal technicality of standing.”

“My legal team and I will carefully review the decision before determining our next step in this important constitutional dispute,” Johnson said. “We’ve lost a battle in court, but we will continue to move forward in our effort to return sanity, fairness and balance to government on behalf of the American people.”

Johnson could ask the panel of judges on the Seventh Circuit to review Tuesday’s decision, or he could ask the Roberts Court to intervene.

Meanwhile, a decision from the Supreme Court on the fate of state-based health insurance subsidies is not expected until this summer.