Pennsylvania Republican Senate candidate David McCormick filed two lawsuits challenging provisional ballots in Philadelphia, signaling he is prepared to take his fight to the Supreme Court.

McCormick declared victory after The Associated Press projected Thursday that he beat incumbent Sen. Bob Casey (D) in the key race. Decision Desk HQ, The Hill’s election data partner, has not yet called the race.

McCormick’s lawyers said Philadelphia plans to adjudicate between 15,000 and 20,000 provisional ballots and that his campaign intends to challenge “large groups” of them for not complying with statutory requirements.

The Republican asked for court permission to challenge batches of ballots collectively rather than fighting each one individually, citing a need for efficiency. McCormick also asked that election officials only be allowed to adjudicate provisional ballots in the presence of a Republican Party representative.

“Plaintiff is concerned that the sheer number of provisional ballots will overwhelm the capacity for individual challenges, creating an impractical burden that risks errors or inconsistencies in the adjudication process,” McCormick’s lawyers wrote in court filings.

“Without the ability to make global challenges, Plaintiffs fear that potentially non-compliant ballots may be improperly counted, compromising the fairness and integrity of the election,” they continued.

Decision Desk HQ reports McCormick leads Casey by 0.5 percentage points, the edge of the threshold that triggers an automatic recount. Casey’s campaign has not conceded and said Thursday that the “count in Pennsylvania is still continuing.”

“The number of provisional ballots expected from areas that favor Senator Casey, like Philadelphia and its suburbs, is further proof that this race is too close to be called,” Maddy McDaniel, Casey’s campaign spokesperson, said in a statement. “As the McCormick campaign admitted in their own lawsuit this morning, the counting of these ballots could have an ‘impact on the outcome of the election.’ With more than 100,000 ballots still left to count, we will continue to make sure Pennsylvanians’ voices are heard.”

The Hill has reached out to Philadelphia’s elections board for comment.

Provisional ballots in Pennsylvania had been the subject of significant litigation before the election.

Pennsylvania’s top court ruled 4-3 that voters who submit deficient mail ballots — such as ones not including an inner, secrecy envelope — were entitled to an in-person do-over by casting a provisional ballot at their polling place. Republicans have argued the additional option runs afoul of state law.

The Supreme Court refused Republicans’ request to halt the decision before the election. But three conservative justices issued a statement making clear they weren’t rejecting Republicans’ underlying claim that the state court was usurping the Pennsylvania Legislature’s constitutional authority in setting voting rules.

McCormick’s new lawsuits set up the possibility the dispute, which is rooted in the “independent state legislature theory,” could return to the justices. The Senate candidate’s lawyers wrote in court filings that the litigation “is ripe for appeal to the United States Supreme Court.”

They asked that the challenged ballots be sequestered until the high court resolves the legal battle.

The lawsuits come as election officials begin their canvass of provisional ballots, which under state law does not commence until the Friday following Election Day. On Thursday, Philadelphia officials said they were still tallying how many provisional ballots were received.

Pennsylvania Secretary of State Al Schmidt (R) estimated Thursday there were at least 100,000 ballots remaining statewide, including provisional, military, overseas and Election Day votes.

“We urge patience as election workers continue to do this important work, especially in contests where the margins are very close,” Schmidt said.

Updated at 11:42 a.m. EST