PHILADELPHIA — The Republican National Committee and U.S. Senate candidate Dave McCormick are suing to temporarily stop Montgomery County from distributing and collecting mail ballots.

The suit, which was filed Friday, also demands the county to hand count all mail ballots that have already been distributed, a process that could add several days to the vote counting process in November.

Montgomery County was the first in the Philadelphia area to begin distributing mail ballots when the county election board announced last Tuesday that ballots were available, just one day after the Pennsylvania Department of State certified the candidates on November's general election ballot.

In a lawsuit filed in the Montgomery County Court of Common Pleas alongside local Republicans, the RNC argued that the county's quick start to mail voting violated Pennsylvania election law because ballots were distributed before the county began state mandated logic and accuracy testing on election systems.

That testing is required before an election begins. By sending ballots before that testing, the RNC argued, Montgomery County began the general election.

“Remarkably, Defendants were aware that the L & A testing had not been completed on Sept. 17, 2024 and public stated it would not commence until Sept. 19, 2024,” the lawsuit said.

As a result, the RNC wants a Montgomery County judge to block the county from distributing ballots until the testing has been completed and to set aside and hand count any mail ballots that have already gone out and are returned.

Montgomery County has become a key Democratic stronghold in recent years that helped swing the state to President Joe Biden in 2020. Turnout in the key county could play a major role in determining the outcome of both the presidential and Senate contents.

In a statement last week, a spokesperson for Montgomery County said the RNC had misrepresented the state's election code in a cease and desist letter that was sent prior to filing the lawsuit.

“We have conducted ballot acceptance testing and are fully complying with the election code and Department of State directives,” county spokeswoman Megan Alt said in an email.

If the RNC's lawsuit is successful it could severely slow down the counting process in Pennsylvania's third largest county by potentially forcing tens of thousands of ballots to be hand counted.

Montgomery County officials said last week they planned to distribute roughly 115,000 mail ballots beginning last week. Any of those ballots returned would have to be hand counted, a process that takes far longer than machine counting.

In April, the county was slow to distribute mail ballots and county officials have said they worked diligently to resolve those issues, becoming one of the fastest counties to distribute ballots ahead of the general election.