Even before election, Trump, allies sue over claims that non-citizens might vote

Donald Trump and his Republican allies are ratcheting up baseless claims that the November 5 US presidential election could be skewed by widespread voting by non-citizens in a series of lawsuits that democracy advocates say are meant to sow distrust.

At least eight lawsuits have been filed challenging voter registration procedures in four of the seven swing states expected to decide the election contest between Trump and his Democratic rival, Vice-President Kamala Harris.

Trump and his allies say the legal campaign, which includes a wide-ranging challenge to the citizenship status of voters in Arizona, is a defence of election integrity.

But their court filings offer little evidence of the phenomenon that independent studies show to be too rare to affect election results, legal experts said.

"The former president is trying to do what he's done the last three times he's run, and set up this 'If I win the election is valid and if I lose the election was rigged' narrative," said New Mexico Secretary of State Maggie Toulouse Oliver, a Democrat. Apart from his more recent presidential bids, Trump briefly ran in 2000 for the Reform Party.

The Trump campaign referred a request for comment to a spokesperson for the Republican National Committee, who said, "We believe our lawsuits will stop non-citizen voting, which threatens American votes."

It is a felony offence for a non-citizen to vote in a federal election and independent studies have shown it rarely happens.

Backers of Trump's strategy say that even one illegally cast ballot is too many.

Ohio Secretary of State Frank LaRose, a Republican, told a congressional panel last week that non-citizen voting is a rarity but that enforcement is necessary to keep it that way. He said his office recently identified nearly 600 non-citizens from state voter rolls that contain about 8 million registrants in total.

"We found 135 this year that had voted. We found another 400 that were registered but hadn't yet voted. And this idea that it's already illegal? It's illegal to hijack airplanes, but we don't get rid of the TSA," LaRose said.

A study of Trump's false claims of widespread non-citizen voting in the 2016 presidential election showed only 30 incidents among 23.5 million ballots cast, accounting for 0.0001% of the vote, the Brennan Center for Justice at New York University said.

Federal law prohibits large-scale changes to voter rolls within 90 days of an election as well as purges that target particular class of voters, such as recently naturalised citizens, which the US Justice Department reminded states of in an advisory last week.