Kentucky is expected to remove up to 250,000 inactive voters from its registration rolls in response to a lawsuit filed by the conservative watchdog group Judicial Watch.

The group alleged that the state has more registered voters than citizens over the age of 18 and that its failure to remove ineligible voters violates the National Voter Registration Act. The Supreme Court highlighted states' responsibility to keep their voter rolls clean in a ruling last year regarding Ohio's voter maintenance laws, according to Real Clear Politics .

Now other states, including Kentucky, are seeing the impact of that decision.

In response to the lawsuit, Kentucky had to mail out confirmation notices to the state's 250,000 inactive voters, according to Judicial Watch's press release. If these individuals don't confirm their current address or don't vote in the next two federal elections, they will be erased from the voting system.

"This is another major victor for cleaner elections, especially following Los Angeles County's agreement with Judicial Watch to begin the process of removing as many as 1.6 million inactive voters," Judicial Watch President Tom Fitton said in the press release.

Under the National Voter Registration Act, states are required to perform voter registration maintenance in order to remove voters who have moved, died, or are unable to vote for other reasons, according to Real Clear Politics.

Though inactive voters aren't necessarily committing voter fraud, they could be individuals who have moved precincts and vote in both locations, or they could have moved to other states and continue to vote in Kentucky through an absentee ballot.

But in some cases, voters could have moved and simply didn't cancel their registration at their old address. Others may have died and their names remain on rolls.

Real Clear Politics pointed to a Pew Charitable Trusts study which looked at 24 million voter registrations in the U.S. and found that one out of eight weren't valid or were inaccurate. At least 2.75 million people were registered in at least two states, while at least 1.8 million registered voters had died.

Like Kentucky, 58 counties in California, including Los Angeles County, are also cleaning their registration rolls after a court settlement with Judicial Watch.

Part of California's voter registration issues have been attributed to the California Department of Vehicles' automatic voter registration system, which the state began using in April 2018 for primary elections.