HARRISBURG, Pa. (CBS/AP) — Pennsylvania’s top election official has asked the state’s highest court to back her up in a new legal dispute with President Donald Trump’s campaign over whether counties should count mail-in ballots when a voter’s signature doesn’t necessarily match the one on their registration. The filing, at midnight Sunday by Secretary of State Kathy Boockvar, a Democrat, comes several days after Trump’s campaign raised the matter in its wider, election-related federal court case in the presidential battleground state.

In guidance last month to counties, Boockvar told them that state law does not require or permit them to reject a mail-in ballot solely over a perceived signature inconsistency.

Her guidance comes amid a surge in mail-in voting and rising concerns that tens of thousands of mail-in ballots will be discarded in the presidential election over a variety of technicalities.

In federal court, Trump’s campaign asked a judge to declare that Boockvar’s guidance is unconstitutional and block counties from following that guidance.

In that case, Trump’s campaign is also trying to remove a county residency requirement on certified poll watchers and ban counties from using drop boxes to collect mail-in ballots.

The fight over signatures is one of many partisan battles being fought in the state Legislature and the courts over mail-in voting in Pennsylvania.

The latest CBS News Battleground Tracker poll shows Democratic nominee Joe Biden leading Trump by seven points — 51% to 44%.

(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)