Senator Brian Schatz's proposal to allow any American to buy into Medicaid is frustratingly vague: we don't know the plan design and how it would be integrated into the ACA marketplace, as David Anderson and Loren Adler point out in this Vox roundup of expert assessment.
Two disclosed details are salient, though -- and to me, point toward two essential features of an ACA redesign from the progressive side. The first is the provider payment rate: bumped up to Medicare. The second is a cap on premiums as a percentage of income -- 9.5% -- for any buyer. (Larry Levitt mentions that feature in the Vox roundup; it's apparently not yet part of any published plan outline.)
Those features bring me back to the compromise package floated by the Urban Institute's Linda Blumberg and John Holahan back in January (which in turn built on their 2015 ACA enrichment plan, with concessions to Republicans salted in). That plan included an 8.5% of income cap on premiums for any buyer -- and a cap on payment rates paid to providers (in concert with reinsurance):
