Jurisdictions once monitored by the justice department for racially discriminatory voting practices have collectively closed more than 1,000 polling places since a watershed 2013 US supreme court ruling released the jurisdictions from oversight, according to a new watchdog report.

In 757 counties and county equivalents that formerly had to pre-clear voting practice changes with Washington, 1,173 polling places disappeared between 2014 and 2018, a study by the Leadership Conference Education Fund, part of the nation’s oldest and largest civil rights coalition, found.

The closures could disproportionately disenfranchise voters of color, especially when combined with restrictive voter ID laws, gerrymandering and aggressive voter roll purges, the report warned. Last month, a separate study found that US election jurisdictions with histories of egregious voter discrimination have been purging voter rolls at a rate 40% beyond the national average.

The top three states for polling site closures were Texas (–750), Arizona (–320), and Georgia (–214), which all have Republican leadership.

The trend has also accelerated with 69% of the recorded closures occurring after the 2014 midterm elections. Thirty-nine per cent of the jurisdictions in the study had seen an overall reduction in the number of polling places between 2012 and 2018.

“Even when [voters] do hear about [polling closures] ahead of time, voters may have to choose between going to a new polling place significantly further away and working enough hours that day to put food on the table – an impossible choice that no one should ever have to face,” the report quotes Beth Stevens, director of the Voting Rights Program at the Texas Civil Rights Project, as saying. “And it’s a choice that usually falls on the most vulnerable voters, thereby reinforcing existing power structures and sending a message to these voters that they are less important than others in the eyes of their government.”

Elections officials mostly did not reply to requests for information about polling closures, the report said.

“Many either did not respond to requests for comment; responded but did not provide meaningful information; or responded with false information,” it said. “By far, the most common justification for closing polling places was no justification at all.”

Officials have defended polling closures by saying the rise of mail-in voting and other changes means fewer polling sites are needed. But the watchdog group warned mail-in voting was not in wide use and no study had been undertaken to evaluate the impact of voting practice changes on minority groups.

“Closing polling places has a cascading effect, leading to long lines at other polling places, transportation hurdles, denial of language assistance and other forms of in-person help, and mass confusion about where eligible voters may cast their ballot,” the report said. “For many people, and particularly for voters of color, older voters, rural voters and voters with disabilities, these burdens make it harder – and sometimes impossible – to vote.”

Texas and Arizona led the way in polling station closures, owing to the states’ conversion to a “vote centers” model, under which voters may cast ballots at any polling station, as opposed to a precinct model. But studies of vote centers indicate a potentially dramatic restriction of voting access in counties with large minority populations. In 2014 in Graham county in Arizona, which is 33% Latino and 13% Native American, half of all polling places were closed in a conversion to vote centers, the study said. Cochise county, which is 35% Latino, closed 65% of its polling places when it converted to vote centers.

In some places, officials advanced claims for polling site closures that were highly controversial, blaming laws requiring wheelchair access and citing concerns about school safety in an age of mass shootings, the report said.

“One of the more alarming trends we discovered is a widespread practice of blaming polling place closures on another civil rights law, the Americans with Disabilities Act (ADA),” the report said. “Election officials took advantage of the public’s lack of understanding about the law to grossly inflate the estimated costs of compliance for both publicly and privately owned polling places.”

One bright spot was in South Carolina, which closed hardly any stations since 2012. “We attribute this to state laws requiring multiple local and state elected officials to approve all polling place closures, a conclusion we arrived at through research and interviews with local advocates,” the report said.

The report warns that without section five of the Voting Rights Act, which established the process of pre-clearance and which was ended with the Shelby ruling, “racial impact analyses are no longer conducted to fully assess the impact of vote centers on Black, Latino, Native American and Asian American voters.

“The myriad tactics now used to restrict electoral participation are just as pernicious as the poll taxes and literacy taxes of the 20th century,” the report said. “Congress can – and must – address this problem by restoring and strengthening the Voting Rights Act.”