The new health care exchanges may have opened with a whimper this fall, but they closed the year with a surge as consumers rushed to meet the Dec. 24 deadline for insurance policies that take effect January 1st. Over 2 million people have now enrolled in private health plans, thanks to the last-minute influx, and 4 million have signed up for Medicaid. The first figure is only a fraction of the Obama administration’s original goal for 2013, but it should comfort anyone who believes the Affordable Care Act can work. It confirms that Americans still want what the law promises, and that the online marketplace can deliver it.

With the online portals now operating smoothly, private insurers may yet sell 7 million individual policies by March 31, when the 2014 open enrollment season ends. But enrolling people is only one of the challenges the administration still faces. On the technical front, it must now manage millions of complex transactions among consumers, insurers and the government agencies that will subsidize much of the new coverage. Equally important, the president must still convince a skeptical and polarized country that Obamacare is right for America.

The technical challenges, though daunting, are starting to look manageable. As a shopping site for insurance, Healthcare.gov now works pretty much as intended, with response times of under a second and virtually no more outages or error messages. But the system will face another critical test in coming days and weeks, as newly insured consumers try to pay their premiums and claim their health care benefits.

While the public-facing portion of healthcare.gov has improved over the past eight weeks, the government has continued to struggle with the back-end mechanisms that insurers need to keep track of new subscribers and bill the government for its share of their premiums. The feds concede that insurers received garbled or erroneous data on 4 to 15% of new enrollees during October and November. As many as 15,000 enrollees may have slipped through the cracks completely, meaning their ostensible insurers never received any electronic records for them.

These transmission problems were largely resolved by early December, but insurers are still scrambling to fix any remaining bugs and identify all the faulty or missing enrollment files. The administration says it is now “comparing lists of enrollees between insurers and [government] records one by one to ensure that we all have accurate enrollment data.” Insurers have now received corrected files for everyone who enrolled (or tried to) during October and November. This week, the insurers will get fully reconciled files for December as well. Officials say they’re “contacting every consumer who has selected a plan through the federal marketplace to remind them to pay their premium and connect with their insurer.”

If these efforts succeed, a million marketplace enrollees will wake up covered and fully accounted for on Jan. 1. But for people who qualify for Medicaid, healthcare.gov is still just a way station. The site can usually determine whether consumers meet their states’ eligibility standards, but it can’t yet share their applications electronically with state Medicaid officials. As a stopgap, the feds are sending state Medicaid offices spread sheets with basic information on potential enrollees. Some states (known as determination states) will automatically approve applicants that healthcare.gov deems eligible. Others (the “assessment states”) will make them re-apply locally for coverage. The administration can’t yet predict when Medicaid will be fully integrated into healthcare.gov.

Despite the consternation they’ve caused, reparable glitches have never posed a mortal threat to health care reform. The real poison has always been political—a persistent lack of public understanding, coupled with the obsessive hostility of GOP lawmakers.

For all his rhetorical gifts, President Obama has yet to explain the Affordable Care Act in a way that inspires a broad swath of the public. His two preferred pitches—you can keep your old coverage if you like it, and you can shop for new coverage effortlessly—disintegrated this fall, as insurers canceled substandard plans and the federal web site was stillborn. And by rushing to appease people angered by the policy cancellations, he managed mainly to embolden critics, who now vilify him for bending the law to suit his own political needs.

Not surprisingly, public support for the Affordable Care Act is hovering near an all-time low—just 35% according to a CNN/ORC poll released Dec. 23—and outright opposition has climbed to 62%. In truth, most exchange shoppers will pay less than $100 a month for basic coverage because 70% of them will qualify for subsidies. No one will be priced out of insurance because of a pre-existing medical condition, and no one will lose coverage in the middle of a crisis because of an insurer’s cap on benefits. Yet only 16% of the new poll’s respondents expect to benefit from Obamacare. Despite all evidence to the contrary, 63% believe the law will increase health-care costs.

The Affordable Care Act was never going to benefit every American. Its rules, taxes, and subsidies are designed to expand—greatly—the number of people who can afford health care, and improve the quality of care they receive. As USA Today reported last week, some people living just above 400% of the poverty level (the upper limit for subsidies) will spend more of their income on health care in 2014. Most will get more coverage for their money, but some will take a small financial hit.

This administration doesn’t like to talk about disruption or sacrifice, let alone the redistribution of resources. At his year-end press conference, the president stuck to the defense that “millions of Americans, despite problems with the website, are now poised to be covered by quality, affordable health care.” It’s a valid claim, and public resistance may finally start to soften as people start to experience the real-life effects of his signature initiative. But at some point, he may have to venture beyond appealing to us as consumers and appeal to us as citizens.