Carlo Allegri / Reuters Sarah Palin's claim that the Affordable Care Act contained "death panels" that would deny health care to older and sicker people was deemed "Lie of the Year" for 2009. It's hasn't gone away.

WASHINGTON -- The good news is that more Americans do not think Obamacare created death panels to pull the plug on granny than those who do. The bad news is a lot of people still think it's true, and many others still aren't sure.

New survey data reveals a depressing 29 percent of respondents still believe the Affordable Care Act includes provisions allowing a committee to cut off medical care for people at the ends of their lives. Public Policy Polling conducted the research on behalf of Ari Rabin-Havt, a SiriusXM host and author of an upcoming book about politicians and lying. Those polled were asked, "To the best of your knowledge, do you think that President Obama’s health reform law establishes a government panel to make decisions about end-of-life care -- sometimes referred to as 'death panels,' or not?"

It doesn't. Period.

But just 40 percent of the more than 1,000 people polled last month gave the correct answer. And three in 10 weren't even sure.

For this, you can thank Republican politicians like former vice presidential candidate and Alaska Gov. Sarah Palin. You can also thank human nature.

Palin popularized the falsehood that Obamacare would let the government kill old people in an infamous Facebook post in August 2009. Other Republicans piled on, and the rest is history.

"The America I know and love is not one in which my parents or my baby with Down Syndrome will have to stand in front of Obama’s 'death panel' so his bureaucrats can decide, based on a subjective judgment of their 'level of productivity in society,' whether they are worthy of health care. Such a system is downright evil," Palin wrote on Facebook at the time.

Every assertion in that quotation is baseless.

The persistence of the death panel myth underscores how difficult -- and even counterproductive -- debunking lies can be. PolitiFact deemed Palin's assertion to be its Lie of the Year for 2009, and the truth about this issue has been fact-checked and repeated over and over and over again.

Yet still almost 60 percent of Americans -- and nearly three-quarters of Republicans -- either think it's true or aren't sure, according to the Public Policy Polling survey.

With results like this, it's no wonder officeholders and candidates make up stuff to scare everyone. It's effective.

Social science research has shown that giving people evidence to disprove something that they think is true can make those people believe the lie even more. Research has also shown that repeating a lie in order to disprove it can just cement it into the public consciousness. Partisanship also plays a role, of course.

These are among the reasons why so many Americans wrongly continue to believe President Barack Obama isn't a natural-born U.S. citizen or that he is Muslim, two other common lies often repeated or left unchallenged by Republican politicians.

So it's not surprising that 45 percent of Republicans in the Public Policy Polling survey still believe in death panels, compared to 21 percent of Democrats and 19 percent of independents. (Although that's an awful lot of Democrats who think their party's president signed a law that kills senior citizens on purpose.)

Here's the reality: Palin's claims and the firestorm they ignited spooked the Democrats who were writing the Affordable Care Act in 2009, so they removed language (co-written by a Republican!) from the bill that would have paid doctors who counseled patients on their end-of-life options.

The idea is to create a financial incentive for health care workers to initiate a conversation about an unpleasant subject so that patients and their families aren't faced with as difficult a choice when the time comes. If the patient wants every step taken to keep her alive, or doesn't, she will have made that decision independently, ahead of time.

Last year, the Obama administration issued a regulation to achieve the same goal. Now, physicians and other medical providers receive a fee when they talk to their patients about whether they want their wishes spelled out in advance of a life-threatening condition.

But organizations like the AARP and the American Medical Association did. They pushed for the new policy and support it. So do more than 80 percent of Americans, according to survey results published by the Henry J. Kaiser Family Foundation in September.

PPP (D) surveyed 1,083 registered voters by automated telephone and over the internet March 24-26, 2016.