The big ballot measure in Tuesday's elections is in Maine, where voters will decide whether, as Jeffrey Young reports, to become the 32nd state (plus the District of Columbia) to adopt expanded Medicaid under the Affordable Care Act.

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