Donald Trump’s “rigged election” shtick is the product of years of conservative fearmongering about voter fraud and election stealing, and it poses a unique challenge to journalists who want to ensure voter confidence in the election process.

Faced with dismal polling numbers in the final weeks of his presidential campaign, Trump has resorted to telling his supporters that the election will be “rigged” -- stolen from him because of widespread voter fraud. He’s repeated that warning frequently on the campaign trail, and nearly half of his supporters now believe him.

The voter fraud talking point – the idea that Democrats will use voters who lie about their identities, dead voters, or undocumented immigrants to cast fraudulent ballots -- has been debunked ad nauseum in research, court decisions, and expert testimony. Politifact rated Trump’s “rigged election” claim a “pants on fire” lie, stating there’s simply no evidence that widespread voter fraud is a real problem, especially in presidential elections.

But even before Trump’s campaign, a growing number of primarily Republican voters began to believe that voter fraud is a widespread problem.

That’s thanks in part to conservative media’s near-constant, baseless fear mongering about voter fraud over the past few election cycles. Right-wing outlets, and especially Fox News, have bombarded audiences with exaggerated or misleading claims of voter fraud to create the impression that Democratic victories at the ballot box are largely the result of illegal election rigging. Stories about dead or non-eligible or non-existent voters appearing on voter rolls are regularly touted as proof of nefarious activity, even though those voter registrations never actually translate into votes.

The most memorable example of this kind of fear mongering came during the 2008 controversy surrounding the non-profit group ACORN. A number of ACORN voter registration employees had been discovered submitting false or duplicate voter registration forms (the laws in many states require third parties who register voters to submit all forms they receive). Fox News devoted countless segments to the story in order to hype hysteria about widespread voter fraud, despite the fact that those forms never produced an actual fraudulent vote. ACORN was eventually cleared of charges of orchestrating voter fraud, but half of all Republican voters still believed ACORN helped steal the election for President Obama in 2012 -- two years after ACORN had closed down.

Misinformation about voter fraud isn’t only the fault of conservative media. As GOP statehouses across the country have pushed for restrictive voter ID laws -- laws aimed at disenfranchising typically Democratic voters -- local news outlets have repeated Republican talking points about the threat of voter fraud without fact-checking them.

That kind of round-the-clock saturation helps explain why so many voters have started to doubt the integrity of elections without evidence that it is a problem. And that doubt poses a real threat to a democracy, which relies on voters trusting and accepting the outcomes of elections.

Trump’s “rigged election” shtick is just one element of a broader problem with media coverage of voter fraud. Regardless of who wins in November, journalists are going to have to be a lot more aggressive about fact-checking right-wing horror stories if they want to restore voter confidence in the election process.