Liberals wanted a national enrollment system under Obamacare. They might just get it. Right now, 36 states rely on HealthCare.gov, the federal exchange, to enroll people in health coverage. At least two more states are opting in next year, with a few others likely to follow. Only two states are trying to get out. That’s precisely the opposite of the Affordable Care Act’s original intent: 50 exchanges run by 50 states. The federal option was supposed to be a limited and temporary fallback. But a shift to a bigger, more permanent Washington-controlled system is instead underway — without preparation, funding...