Trump has so far refused to say unequivocally that he will respect the results of the upcoming election, which will see him go up against Vice President Kamala Harris, the Democratic candidate.

During a presidential debate in June, he said he would accept the outcome only if “it’s a fair and legal and good election”. He then quickly added that he would have “much rather accepted” the 2020 results, too, “but the fraud and everything else was ridiculous”.

More recently, on September 7, Trump posted on his Truth Social platform that, if he wins in November, “those people that CHEATED will be prosecuted to the fullest extent of the Law, which will include long term prison sentences”.

He said that could include lawyers, donors and “corrupt election officials”, among others.

“Those involved in unscrupulous behavior will be sought out, caught, and prosecuted at levels, unfortunately, never seen before in our Country,” he wrote.

In this election cycle, much of Trump’s voter fraud narrative has focused on people who are not American citizens.

But Carter at the Brennan Center described this as a “non-issue”. Non-citizen voting is illegal under US law — incurring penalties such as imprisonment and possible deportation — and research shows it is extraordinarily rare.

Yet Republicans, who have made anti-immigrant policies a central plank of their party platform, falsely claim Democrats are allowing undocumented immigrants into the country in order to get their votes. In June, the Republican-controlled House of Representatives even passed a bill requiring proof of citizenship to cast a ballot.

The notion that the US is rife with voter fraud has become a “boogieman” of sorts, Carter explained, and Trump and his allies are using it as “a false justification for efforts to undermine valid election results”.

It is also being used to justify a wave of voting restrictions across the country.

Some states have made it harder to register to vote and cast mail-in ballots or have ushered in stricter voter identification requirements.

“The most aggressive years for restrictive voting legislation in the past decade have come after the 2020 election, and that’s not a coincidence,” Carter said.

She told Al Jazeera that Americans in 28 states are going to face curbs this November that weren’t in place the last time they voted for president. “The policies all share one thing in common,” she added, “which is that they do disproportionately burden voters of colour.”

Many of the new voting restrictions have been implemented in swing states that saw hard-fought races in 2020. These same states are expected to be close again when Trump goes up against Harris in November.

For example, Georgia and Florida have both made it harder to vote and heightened the risk of intimidation, the Brennan Center said in a recent report. North Carolina also put in place more barriers to casting a ballot.

Meanwhile, efforts to put election deniers into key positions in the US electoral system also are drawing alarm.

In the battleground state of Georgia, for instance, the state electoral board passed a new rule in August that could delay election certification — the process whereby a vote count is confirmed — if local officials raise concerns about the accuracy of the vote.

“Certification is supposed to be a ministerial process, a formality, that happens after an election is over,” said Carter. “But it has now been increasingly politicised, so that efforts to block certification are efforts to subvert election results.”