Rights group in the US are calling for a return to hand-counted paper balloting as a universal standard for elections in an effort to boost transparency and prevent vote irregularities that many see as a threat to the country's democratic system.

Shyla Nelson, the co-founder of Election Justice USA, told Al Jazeera that a complete overhaul of the system, including the end of the use of electronic voting machines, is required to ensure truly democratic elections in the country.

"Until we systematically address the myriad ways in which our elections are manipulated - voter suppression, unauthorised registration purges, district gerrymandering, gross exit poll variances, the privatisation of voting machinery, and the lack of transparency in ballot processing - our elections will continue to rank among the lowest in the world in integrity."

Nelson criticised current government initiatives to protect the voting machines - which she noted are in many cases running on increasingly obsolete hardware and software - from cyber attacks as a failure to address "the well-documented reality of election fraud at their root".

US Department of Homeland Security chief Jeh Johnson said on Wednesday that the government would "carefully consider" whether the country's election system should be considered as critical infrastructure, a move that would trigger greater digital security measures for electronic voting machines.

"We’re actively thinking about the election and cybersecurity right now," he told reporters.

But Caitriona Fitzgerald, the chief technology officer of the Electronic Privacy Information Center (EPIC) - a civil rights group, told Al Jazeera that the very reliance on electronic voting machines and online voting threatens public trust in US elections.

'Election security'

"Paper ballots are a very important element in election security. Without a paper record of one’s vote, it is impossible to verify if the computer has, indeed, recorded your vote in the system as it is shown on the screen.

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"Furthermore, lack of a paper record makes meaningful recounts or audits impossible because any recount would simply corroborate the same count the computer made the first time and would not catch any errors."

Clifford Arnebeck, a civil rights attorney who co-chairs the Alliance for Democracy, and has filed multiple lawsuits over alleged election fraud in the US since 2000, told Al Jazeera how it has become much easier to manipulate votes.

"In 2004 - there were still punch card ballots and optical scan ballots - so the flipping of votes had to be done manually by taking ballots to unauthorised locations and reshuffling the deck.

"But with the electronic system, it is much more simple to use a program to flip the tabulation of vote."

The calls for more transparency came after widespread accusations that the Democratic primary was rigged in favour of Hillary Clinton and against her rival Bernie Sanders.

But Gary Nordlinger, a state attorney and professor of politics at George Washington University, told Al Jazeera that it is highly improbable that the US ever faced election fraud, saying the polling system has always been tightly controlled.

He also pointed to Clinton's substantial margin of victory as proof of the unlikelihood that any significant vote manipulation occurred, especially when there are "election observers" at the polling stations.

"Hillary Clinton would not have won by around 3.8 million votes if there was election fraud," he said.

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However, Arnebeck says he has garnered much evidence pointing to use of sophisticated technology to rig electronic voting machines across the country and plans to launch a lawsuit over the alleged fraud in the Democratic primary.

"This is the most extreme case of election fraud yet ... the new technology is believed to be capable of stealing 50 (percentage) points in an election," he said.

'Sanders was winning by landslide'

"Sanders was winning by a landslide ... so they had to flip whatever votes they could. That is one of the reasons why the evidence is so compelling."

Election Justice USA released a report last month that detailed its alleged evidence of election irregularities and fraud in the Democratic primary and pointed out the lack of transparency practices.

"Unlike other technologically advanced countries such as Germany, Canada, France, Ireland, Italy, Denmark, Finland, and 53 other countries, election ballots in the United States are not counted by hand and in public," the "Democracy Lost" report said.

"Many US states use touch-screen computer voting systems that do not even generate a paper trail. Almost all ballots, whether paper or not, are counted by computers.

"All counting is non-transparent and inaccessible for verification by the public. The few states that audit the computer counts by hand only examine a tiny percentage of the ballots and even this count is not performed according to proper statistical procedures.

"In other words, the results of our elections, based on computer counts, are largely unverified."