Sen. Richard H. Black, R-Loudoun, left, an opponent of Medicaid expansion, walks past a group of protesters who are in support of Medicaid expansion outside the State Capitol in Richmond, VA Monday, May 14, 2018. The Virginia Senate returns today to deal with the state budget and Medicaid expansion.(AP Photo/Richmond Times-Dispatch, Bob Brown).
Sen. Richard H. Black, R-Loudoun, left, an opponent of Medicaid expansion, walks past a group of protesters who are in support of Medicaid expansion outside the State Capitol in Richmond, VA Monday, May 14, 2018. The Virginia Senate returns today to deal with the state budget and Medicaid expansion.(AP Photo/Richmond Times-Dispatch, Bob Brown). Credit: Richmond Times-Dispatch — Bob Brown

Medicaid expansion is still going strong. And Virginia may have just given us a preview of another wave.

The Virginia Legislature on Wednesday, despite very narrow Republican majorities in both chambers, voted for the piece of Obamacare that the Supreme Court had made optional for the states. After Virginia, there are only 17 holdouts — including Texas and Florida.

What’s really important is that no state has gone in reverse, even those states that switched from Democratic to Republican governments after implementing expanded Medicaid. I’m going to take a short victory lap on my prediction from five years ago: “The future of this is now pretty clear: It’s going to work just as the original Medicaid roll-out did. That was also optional for states, and many of them declined the first time around, but eventually all 50, no matter how conservative, found themselves participating. The key — and I expect this to be true of the ACA Medicaid expansion as well — is that the decisions were one-way. Over time, some of the decliners decided to join, but no state walked away.”

Why? For one thing, it’s always very difficult to take government benefits away from large groups of citizens. They tend to notice! And, for another, the Affordable Care Act set out a pretty good deal for the states, so it doesn’t make much financial sense to drop out (or, for that matter, to resist in the first place). It’s true politicians don’t always do what’s in a state’s fiscal interests, but it’s a pretty big factor making it hard to drop out.

It is true that the Donald Trump administration has granted looser waivers for state variations — the idea of waivers were part of the original law, which was designed to allow state experimentation — that have, in the eyes of Obamacare supporters, undermined Medicaid expansion to some extent. Still, those who follow this closely don’t think it’s equivalent to actually shutting down the program.

Virginia had a unified Republican government when the Supreme Court set up these rules. Democrats elected governors in 2013 and 2017 and sharply narrowed the Republican majority in the lower chamber of the state Legislature last year. This was the result.

And if this fall’s elections go the way they appear to be headed, Democrats are going to pick up plenty of state legislative seats, including a handful of chamber majorities, and perhaps another handful of governorships. Health care policy will likely follow in at least a few of those 17 holdouts. There are also at least two states, Idaho and Utah, that have ballot measures on the subject in November.

It’s possible that if Republicans retain their unified government at the federal level and pick up a few Senate seats, they could actually manage to eliminate the Affordable Care Act after all. But so far, it looks like Medicaid expansion is a one-way street, and if so, eventually the whole nation will get there.

Jonathan Bernstein is a Bloomberg Opinion columnist.