States Report Medicaid Surge After Obamacare Rollout

Some states are signing up tens of thousands of new Medicaid enrollees in the initial weeks of the health law's rollout, while placing far fewer in private health insurance—a divergence that suggests Medicaid expansion may be a larger part of the law than expected.

In one sense, the Medicaid figures are good news for the Affordable Care Act's advocates, who hoped the law would reduce the number of Americans without health insurance.

But the predominance of Medicaid enrollees so far could also fuel criticism that the law will lead to a greater government grip on the health-care system, instead of leaving room for private health insurers to grow.

Even before HealthCare.gov launched with glitches, Medicaid expansion was expected to play the leading role in bringing coverage to Americans in 2014. The Congressional Budget Office projected in May that nine million Americans would be added to Medicaid's rolls in 2014, while it said seven million would sign up for private coverage through new health-insurance exchanges.

The troubles of the federal website—which serves consumers in 36 states that don't run their own insurance marketplaces—are putting that seven million figure in jeopardy. The Medicaid expansion, however, looks closer to being on track.