I have just made my way through the states' brief in Florida v. HHS for the second time, and something stood out to me in the states' challenge to the ACA's Medicaid amendments. Specifically, the states (1) do not appear to be resting anymore on a claim of reliance on the program remaining largely unchanged, but instead (2) rely principally on the claim that losing all of their Medicaid funding for failing to adhere to the ACA's conditions is disproportionate, and thus coercive.
This is an important shift in emphasis, and it is understandable strategically. It avoids some of the obvious problems with the general argument that simply too much money is at stake for the states to say no. But it also raises a number of new problems, the most obvious of which is this: I do not think it has been established that the federal government would, in fact, withdraw all of a state's Medicaid funds if it failed to completely adhere to the ACA's new requirements. The Secretary of HHS would have the statutory authority, but such a theoretical possibility, in itself, may be a ways from showing coercive pressure--especially if the Secretary has the discretion to take intermediate measures, such as only withholding the ACA-related funds.
In any event, this seems like an important shift in the terrain of the argument.