In theory, no one should be surprised that it was health care that opened the first big crack in the Trumptime GOP. It's been obvious for ages that the Republicans didn't have any kind of consensus on how to fulfill their promise of replacing the Affordable Care Act. If you put that first on the legislative agenda, of course it's where the splits are going to start showing.

Yet it still feels weird. There are issues—immigration, foreign policy—where the Republicans have clear public divisions. Health care has not traditionally been one of those topics. Like abortion, it brought the party together: Everyone could join hands and damn Obamacare. So the GOP hasn't just been fractured by something big; it's been fractured by something that seemed central to its self-identity.

The longer the spotlight lingers on health care, the stranger the ensuing debate is going to seem. Already this month we've had one prominent Republican (and Trump crony), Newsmax chief Christopher Ruddy, calling for a Medicaid expansion plan that sure sounds a lot like the public option. Now, I certainly wouldn't bet on that becoming the next big Republican proposal. (I wouldn't bet on the next big Republican proposal having much to do with health care at all.) But I won't be surprised if we see that idea or others like it getting more traction within the party. A sizable chunk of the base is already open to such notions. (In a Gallup poll last May, 41 percent of Republicans said they'd favor replacing the Affordable Care Act with a federally funded system.) There are ways to frame the proposal that might make it seem like less of an odd fit with the party's pro-market rhetoric. (Ruddy's column takes care to point out that the status quo isn't a free market. He's right about that, though his solution isn't exactly a free market either.) And it's not as though the party has never embraced a health entitlement before. The last Republican president gave us Medicare Part D, and the last Republican presidential nominee accused Obama of cutting Medicare.

There will also be a lot of Republicans who hate the idea, of course. But my point here isn't that I think the GOP is about to move to the left of Obama on health policy. It's that the continents are drifting, and you really don't know where everyone will be standing in a few years. Washington may be dominated by one political party right now, but there's a bunch of parties within that party and we're just starting to see the battles between them.

Related: "The meaning of 'fundamentally conservative' and 'fundamentally liberal' is extremely unstable."