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The battle over who gets to vote in the US has intensified against the backdrop of Kamala Harris reigniting Democrat hopes of retaining the White House.
Her Republican challenger, Donald Trump – who is already claiming November's election will be rigged – has seen his poll lead evaporate since Ms Harris replaced Joe Biden as the Democratic candidate.
Republicans concerned over voter fraud are tightening election restrictions, amid Democrat accusations that their efforts are a sustained attempt to suppress voting rights.
About 400 measures have been passed since the start of the year across the country, including tighter voter identification laws, banning ballot drop boxes and making it easier to challenge voter registrations en masse.
Other bills have made postal voting more difficult, and some states are imposing residency requirements aimed at reducing the number of students who can vote.
True the Vote, a Texas-based group at the heart of the campaign to impose tighter election restrictions, says fraud is rampant.
Among the abuses given by the group – founded by conservative activists Catherine Engelbrecht and Gregg Phillips in 2010 – is the manipulation of mail ballots by what it describes as “vote harvesting”, which involves providing precincts with ballot applications and gaining voters’ signatures by “deception, intimidation or forgery”.
The group alleges that some of those who receive a ballot are legally barred from voting.
It also claims campaign workers “insert themselves” into the voting process by claiming to be election officials whose assistance includes filling out the ballot.
To prevent such interference, True the Vote has developed an app that compares voter and postal data. It has been used to challenge more than half a million registrations.
Georgia, where Mr Trump asked Secretary of State Brad Raffensperger to “find” 11,780 votes after the last election, is at the tip of the spear when it comes to fighting voter fraud.
In May, Governor Brian Kemp signed a bill that, among other things, made it easier for voters’ appearance on the electoral roll to be challenged. It was building on earlier laws dating to 1940, when white supremacists contested the rights of black people to cast their votes.
The latest version has enabled a person to object to hundreds of voters at a time.
Republican state senator Max Burns, who sponsored the measure, said it would “pave the way for fair elections that uphold the voice of every Georgia citizen”.
The local branch of the American Civil Liberties Union took a different view, saying it lowered the barrier “for making biased and baseless voter challenges around the state”.
These challenges to voters' appearance on the electoral roll are being replicated in other states, either by conservative groups or officials in states such as Ohio and Tennessee.
The campaign is being aided by sophisticated software that compares an array of databases from the electoral register to criminal records – which can disqualify an elector – and address data.
Florida is cracking down on voter registration organisations believed to be involved in ballot harvesting. Arkansas has set up what it describes as an “election integrity unit” which, among other things, bans officials for sending out unsolicited postal ballot applications.
Texas has toughened the penalties imposed on convicted criminals who vote illegally.
And in Arizona, Republicans have taken a complicated case to the Supreme court that could disenfranchise thousands of voters.
Republican Jeff Lord, who served in Ronald Reagan’s administration, believes the tightening of election laws is justified.
“It comes down to this: Republicans want voter ID for election security and Democrats say this is voter suppression,” he told The National.
“It is really saying that the Democrats think they can get away with breaking election law and that would be stopped with Voter ID. Here in Pennsylvania, if you want to buy a bottle of booze, you have to show your driving licence. It is the same principle for voting.”
He said Pennsylvanian Republicans have had plenty of experience in elections in which there has been “funny business”.
“If you get into mail voting, you have people filling in ballots for others. The whole things is a mess,” Mr Lord said.
However, there is mounting evidence that stricter ID laws would disenfranchise millions of Americans who are entitled to vote.
A survey conducted by groups including the Centre for Democracy and Civic Engagement at the University of Maryland and the Brennan Centre for Justice found that 9.1 per cent of Americans of voting age lack government-approved ID, such as a passport or driving licence.
That works out to 21.3 million voters, with citizens of colour more likely to fall foul of these laws than white people.
“A lot of it is rooted in how the US does elections. In a lot of countries, you don’t have to do it, or the government does it automatically,” Christopher Galdieri, professor of politics at Saint Anselm College in New Hampshire, told The National, referring to voter IDs.
“In the US, that responsibility is pushed on to individual voters. That creates all sorts of opportunities if you are looking to change what the electorate looks like or try to get people kicked off registration lists.”
Mr Galdieri said “a tonne of money” is being put towards efforts to challenge voter registrations.
“There are lots of lawyers and people being hired to do this sort of thing. It is a reflection of where Republicans are these days,” he said.
“Once upon a time, you won elections by getting more votes and now it’s about shaving people off the elections register.
“There are people who vote where they shouldn't or try to vote twice. But the number of votes involved are absolutely tiny.”
