Republicans plan to ask the Supreme Court to review a major Pennsylvania state court ruling that extended the due date for mail ballots in the key battleground state, teeing up the first test for the Supreme Court since the death of its liberal leader Justice Ruth Bader Ginsburg.

The GOP legal strategy, which was revealed in a pair of court documents filed overnight and Tuesday morning, has not been previously reported.

The development comes after the Pennsylvania Supreme Court dealt Republicans a major blow last week in a bitterly partisan election lawsuit that could help determine whether President Trump or Democratic nominee Joe Biden takes the Keystone State, which Trump won in 2016 by just over 44,000 votes.