The coalition of state attorneys general defending the Affordable Care Act have taken the first step in appealing a federal judge's ruling in Texas that declared the entirety of the 2010 law unconstitutional.

The group of states, led by California Attorney General Xavier Becerra, are expected to argue that the law's individual mandate remains constitutional despite a federal tax law passed in 2017 that zeroed out its tax penalty. The AGs contend that even if the individual mandate is struck down, the rest of the law's provisions should be allowed to stand.

The states filed their notice of appeal in the Northern District of Texas on Thursday. The attorneys general in a call with reporters described the underlying ruling by U.S. District Judge Reed O'Connor of the Northern District of Texas as based on a “flimsy theory” and “ludicrous.”