As Republican lawmakers set the legal groundwork for a swift dismantling of the Affordable Care Act, a new NPR/Ipsos poll (PDF) found that most Americans still don’t have a firm grasp of the law—and what’s at stake.

The law’s biggest success was that the number of uninsured dropped to the lowest rate in United States history—just 9 percent. But when Americans were asked how the ACA affected the number of uninsured, 51 percent got it wrong, responding either that the number of uninsured increased, stayed the same, or that they didn’t know.

Bill Pierce, a senior director at APCO Worldwide, which advises health care companies on strategic communications, told NPR that the law’s shaky start with healthcare.gov may have planted a bad seed in people’s minds. And the years-long rollout of the law helped create a disconnect. “By the time the insurance rate started to fall, a lot of minds were already set,” he said.

Questions on details of the ACA drew more mixed results from those polled. Most people were aware that the law requires insurance companies to cover preventative care and bars them from discriminating against those with preexisting conditions. Yet only 18 percent correctly responded that the law didn’t set limits on end-of-life care. That low rate may be thanks to unfounded accusations about "death panels" during the 2008 election.

Nevertheless, Americans were still largely supportive of the law. Only 14 percent—or about one in seven—wanted a complete repeal of the law without a replacement of similar legislation. Thirty-eight percent want to see the ACA strengthened or expanded, while 31 percent want a repeal and replacement.

The poll was carried out between January 4 and 5 and involved 1,011 adults.