Georgia’s largest counties failed to prepare for heavy turnout in the state’s fiercely contested 2018 elections, resulting in wait times of up to four hours at the polls and delays in processing registration forms and mailing absentee ballots that ultimately kept some voters from casting ballots, according to a federal lawsuit.

The American Civil Liberties Union filed suit Monday in U.S. District Court in Atlanta on behalf of Georgia Shift, a group dedicated to increasing turnout among young voters. It says Fulton, DeKalb, Cobb and Gwinnett counties in metro Atlanta effectively disenfranchised voters by failing to provide enough polling sites, voting machines and staff.

“The November 2018 elections were plagued with problems that placed inexcusable and unjustifiable burdens on the right to vote,” the lawsuit said.

The ACLU’s suit targets local officials for their role in elections that also brought intense criticism for Georgia state officials including Gov. Brian Kemp. The new Republican governor oversaw the 2018 midterms as Georgia’s secretary of state while he ran one of the most closely watched U.S. gubernatorial campaigns against Democrat Stacey Abrams.

Voting rights groups, including one launched by Abrams after the election, say Kemp and others enforced policies that suppressed turnout in the state. Kemp denies any wrongdoing and said last week that Democrats “need to quit playing politics.”

While the secretary of state serves as Georgia’s top election official, voting is overseen by local election boards in each of the state’s 159 counties. Nearly 4 million voters cast ballots in Georgia last fall, a record turnout in the state for a non-presidential year.

The ACLU lawsuit asks a judge to order the four counties named as defendants to make improvements that ensure the same problems reported last year don’t resurface in the 2020 elections. It says insufficient staffing by local election boards not only contributed to long lines on Election Day, but also slowed processing of registration forms that kept some new voters from voting early. Delayed mailing caused some absentee ballots to arrive too late for others to vote, the lawsuit said.

Fulton County government spokesman Darryl Carver and Gwinnett County spokesman Joe Sorenson declined to comment, citing policies against discussing pending litigation. Spokesmen for the other two counties did not immediately return phone messages.

Scrutiny of the way Georgia administers elections hasn’t let up since November. State lawmakers have been embroiled in heated debates over how best to replace Georgia’s aging voting machines , which lack a paper record that can be audited. The advocacy group Abrams launched filed its own lawsuit challenging the way Georgia conducts elections. And a congressional committee controlled by Democrats is investigating reports of voting problems in the state.