Republican Senate candidate Dave McCormick stepped up his legal efforts to block the counting of undated mail ballots Friday, as incumbent Democrat Bob Casey came to the defense of four county election boards that defied the Pennsylvania Supreme Court and voted to include them in their final tallies.

Election officials say 80,000 ballots remain to be counted then votes in all 67 counties will be tallied again.

Republican Dave McCormick won the U.S. Senate election in Pennsylvania, Decision Desk HQ projected on Thursday, beating Democratic incumbent Bob Casey in an important win for Republicans hoping to capture a majority in the chamber.