On Monday Politico ran a column by Sen. Ron Wyden (D-Ore.) taking issue with my critique of his proposal to accelerate the granting of waivers under Obamacare. Unfortunately, he missed a central point I was making about limitations on the waivers that could be granted.

Apparently the senator was offended by this paragraph, from my New England Journal of Medicine piece on his bill:

Even more problematic to proponents of state flexibility on both the left and the right is that states would not be able to fold other health programs into their waiver request. Liberal skeptics at the Physicians for a National Health Program, for instance, point out that provisions of Medicare, Medicaid, the State Children’s Health Insurance Program (SCHIP), Taft–Hartley plans, and other programs could not be waived, leaving large obstacles in the path of a potential single-payer system. And on the other hand, by leaving Medicaid intact, including the required expansion of the program under the ACA, Wyden–Brown does little to comfort conservatives who envision a privatized voucher approach.

Sen. Wyden contends that states could include Medicaid waivers in any submission to HHS under his bill. He is correct only in the narrow sense that they can continue to do that to a very limited degree now, as under the previous law and during the previous administration.

Yes, modest tweaks to Medicaid would still be possible. But my point was that the central, legislated provisions of Medicaid and other programs–including the large expansion of Medicaid required under Obamacare–cannot be waived. Thus Wyden-Brown would not allow states to pursue a very different route–such as single-payer or a truly market-based system–if they wished. As I wrote, it is “short on state flexibility.”