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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 the nation’s history—just 9 percent. Yet, 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.