The big ballot measure in Tuesday's elections is in Maine, wherevoters will decide whether, as Jeffrey Young reports, to become the32nd state (plus the District of Columbia) to adopt expanded Medicaid under the Affordable CareAct.

Yes, this is big news. The history so far of Medicaid expansionis that it's a one-way street: States that go for it don't exit,even when anti-Obamacare Republicans are elected vowing to doexactly that. As Sarah Kliff observes, if this issuccessful, expect similar measures in those states that havevoter-initiated ballot measures but haven't expanded Medicaid sofar. At the same time, Democrats will probably pick off a fewgovernor seats and state legislature chambers in the 2018 midterms, perhaps allowing them to acceptthe Medicaid expansion in a handful of states.

Certainly that's good news for Affordable Care Act supporters,especially coming out of the defeat of the Republican repeal effort in Congress thisyear.