Many of the most visible moves can be seen in the battleground states that will decide the presidential election, states like Nevada where protests by supporters of former president Donald Trump broke out after the 2020 election.
This year, a security fence rings the scene of some of those protests - the Las Vegas tabulation centre. Nevada Governor Joe Lombardo said last week he had activated a "limited contingent" of 60 members of the National Guard to ensure a timely response to any challenges.
In Arizona, a similar metal fence has been erected at Maricopa County vote tabulation centre in downtown Phoenix, a flashpoint in 2020 for rigged election conspiracy theories and threats against election officials.
-Reuters
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