The U.S. Court of Appeals for the Sixth Circuit on Thursday probed whether a prior ruling under the now-discarded Chevron doctrine still applies to a challenge to a federal agency regulation requiring Title X-funded family planning clinics to refer patients to abortion providers if they request it.

Tennessee is seeking a preliminary injunction to block the 2021 rule, which the state argues violates Section 1008 of Title X’s bar on funds going to “programs where abortion is a method of family planning.”