Behind the scenes, much of HealthCare.gov is still under construction

The Obamacare website may work for people buying insurance, but beneath the surface, HealthCare.gov is still missing massive, critical pieces -- and the deadline for finishing them keeps slipping.

As a result, the system’s “back end” is a tangle of technical workarounds moving billions of taxpayer dollars and consumer-paid premiums between the government and insurers. The parts under construction are essential for key functions such as accurately paying insurers. The longer they lag, experts say, the likelier they’ll trigger accounting problems that could leave the public on the hook for higher premium subsidies or health care costs.

It’s an overlooked chapter in the health care law’s story that has largely escaped scrutiny because consumers aren’t directly affected. Yet it bolsters the Republican narrative that the government has mishandled the implementation of Obamacare.