TEN THOUSAND people a day are submitting health-care insurance applications in California, a state where officials embraced President Obama’s Affordable Care Act. Kentucky’s governor has presided over a relatively error-free implementation of the law in his state, showing leaders across the South what they could do if they cooperated instead of rooting for the policy to fail.

You would have expected similar results in Democrat-controlled Maryland, where officials decided to take charge, instead of punting responsibility for new insurance marketplaces to the feds. Instead, the state’s rollout, led by Lt. Gov. Anthony G. Brown (D), has been an embarrassment.

Maryland started strong after Congress passed the reform. The state approved a series of laws in preparation for the rollout. It was blessed with active public-health nonprofits ready to push implementation. With only 6 million residents, Maryland isn’t nearly as big as 38 million-strong California, which means its Web site would not have to handle massive numbers. Mr. Brown, the state’s health-care point man, is running for governor, so he had a lot to gain from a smooth rollout.

Despite all that, the number of people enrolling through the state’s insurance marketplace is extremely low. The state estimated that 150,000 Marylanders will enroll by March. That, along with new Medicaid enrollments, would put a real dent in the state’s 800,000 uninsured. But only 3,024 people have enrolled in health-care plans through the Maryland Health Connection marketplace, and the state languishes near the bottom of the list when it comes to the percentage of the population that has applied for coverage. Maryland has enrolled a large number of people into the expanded Medicaid program. But the success of that program does not depend on lots of young and healthy enrollees. The marketplace does.

The problem is technical. A buggy Web site freezes on people shopping for insurance, among other problems. Some involved in marketplace enrollments have tried to use paper applications but, The Post’s Lena H. Sun reported, even that backstop isn’t working well. In October, Mr. Brown said that the state was having trouble connecting with broken federal systems. But that can’t explain why Maryland lags behind other states; every state operating its own marketplace faced the same issue.

As with the federal rollout, it is crucial that those responsible fix the glitches soon, well before coverage deadlines, or else the broader policy could falter. Those at the top also have explaining to do. Mr. Brown has admitted that he didn’t know the system was buggy before it launched. As a predictor of leadership, that’s not encouraging.