A federal judge overseeing the latest lawsuit challenging the Affordable Care Act questioned claims from Democratic attorneys general defending the constitutionality of the health law during oral arguments Wednesday.

The line of questioning from U.S. District Judge Reed O’Connor often echoed assertions made by the Republican officials from 20 states who brought the suit. They argue the ACA is illegitimate now that Congress has repealed the law’s tax-based penalty on people who don’t have health insurance.