Christine Gregoire, the governor of the State of Washington, today filed papers in the Sixth Circuit indicating her intent to file an amicus curiae brief in Thomas More Law Center v. Obama in support of the ACA's constitutionality. It is unclear whether or governors or state governments will be joining her brief.
Governor Gregoire's involvement illustrates a point that some reporting on the ACA litigation has either missed or glossed over. Specifically, it's an oversimplification (or perhaps even incorrect) to claim that "28 states" are now challenging the constitutionality of the ACA. For some states, who represents the state, as such, is unclear. The attorney general may have final litigating authority, but if the governor actively opposes the attorney general's position, what is the position of "the state" as an entity?
Washington (represented by state attorney general Rob McKenna) is one of the 26 plaintiff states in Florida v. HHS. So its governor and its attorney general are now both involved, but on different sides.