Kirkland & Ellis partner Paul Clement, the veteran appellate advocate and former U.S. solicitor general, has joined a chorus of conservative lawyers questioning the Justice Department’s decision to stop defending the Affordable Care Act.

Clement, speaking on a panel Wednesday at the Federalist Society’s annual executive branch review conference in Washington, said there are potential “costs to the system” when the Justice Department doesn’t defend federal laws under a traditional duty to defend acts of Congress.