A Texas judge has blocked an order allowing only one absentee vote drop-off point per county, claiming it would affect older and disabled voters.
Drop-off points were set up to allow voters to submit ballots in advance rather than rely on the postal service.
Texas Governor Greg Abbott, a Republican, said the number of drop-off points needed to be minimised to guarantee voter security.
Democrats said the move was blatant voter suppression.
A record number of people are expected to vote by mail in this year’s election due to the pandemic.
The US Postal Service already has already warned ballot papers may not arrive in time to be counted on election day, 3 November.
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Texas has a limit on who can request absentee ballots. Only voters who are over 65, have a disability, are in jail or who will be out of town on election day are allowed to vote by post.
Judge Robert Pitman ruled that the order would have left many voters having to travel long distances to find a drop-off point, or leave them vulnerable to coronavirus if they were forced to vote in person at a polling station.
Governor Abbott’s ruling would have meant some people in Harris County, home to more than four million people, would only have one point in the entire county to hand in their ballot paper.
The race to claim Texas’ 38 Electoral College votes this election is expected to be tight.
President Donald Trump has previously criticised postal voting, claiming there is widespread fraud involved. The Federal Election Commission has rejected these claims.