LAS VEGAS (AP) — The Republican National Committee on Friday filed a federal lawsuit seeking to prevent Nevada from counting mail ballots received after Election Day, as the state’s law currently permits.

The law, passed by Democrats in 2021, permits the tallying of mail ballots received up to four days after Election Day, provided the envelopes are postmarked before the end of the day. The lawsuit says the provision also assumes that envelopes received three days after Election Day that don’t have a postmark indicating otherwise were posted in time.

Republicans contend this violates the U.S. Constitution’s requirement that there be a single day for Election Day.

“Nevada’s ballot receipt deadline clearly violates federal law and undermines election integrity in the state,” RNC Chairman Michael Whatley said in a statement. “Ballots received days after Election Day should not be counted.”

The lawsuit comes after Republicans sued to overturn laws permitting the tallying of ballots received after Election Day in Mississippi and North Dakota, and it’s the 83rd election-related suit filed by the party six months before Election Day. That’s a sign of both the increased pace of election-related litigation and the party’s focus on fighting over election rules after former President Donald Trump installedloyalists who have parroted his false claims about the 2020 election being stolen from him.

Nineteen states, including Nevada, allow ballots to be tallied if they’re received after Election Day. Supporters of those rules say they make it easier to vote and ensure that those who cast ballots by mail have as much time to make up their minds as those who vote on Election Day. Opponents contend they slow election results, undermine trust in the system and can be exploited.

“I hope the RNC is putting as much time and energy into educating voters on how to participate in elections as they put into suing the state of Nevada,” the state’s Democratic secretary of state, Francisco Aguilar, said in a statement.