HARRISBURG, Pa. (AP) — Fresh off another rejection in Pennsylvania's courts, Republicans on Thursday again asked the U.S. Supreme Court to block President-elect Joe Biden’s victory in the battleground state, while the state's lawyers say fatal flaws in the original case mean justices are highly unlikely to grant it.

Republican U.S. Rep. Mike Kelly of northwestern Pennsylvania and the other plaintiffs are asking the high court to prevent the state from certifying any contests from the Nov. 3 election, and undo any certifications already made, such as Biden’s victory, while its lawsuit is considered.

They maintain that Pennsylvania’s expansive vote-by-mail law is unconstitutional because it required a constitutional amendment to authorize its provisions.

However, in a sign that the case is likely too late to affect the election, Justice Samuel Alito ordered the state's lawyers to respond by Dec. 9, a day after what is known as the safe harbor deadline. That means that Congress cannot challenge any electors named by this date in accordance with state law.

Biden beat President Donald Trump by more than 80,000 votes in Pennsylvania, a state Trump had won in 2016. Most mail-in ballots were submitted by Democrats.

Pennsylvania's Supreme Court threw out the case Saturday. Kelly's lawyers sought an injunction Tuesday in the U.S. Supreme Court, then withdrew it while they asked the state's high court to halt any certifications until the U.S. Supreme Court acts. The state's justices refused Thursday, and Kelly's lawyers promptly refiled the case in the U.S. Supreme Court.

In the state’s courts, justices cited the law’s 180-day time limit on filing legal challenges to its provisions, as well as the staggering demand that an entire election be overturned retroactively.

In addition to challenging the state's mail-in voting law, Kelly’s lawyers question whether the state's justices violated their clients' constitutional rights by throwing out the case on the basis of time limits and barring them from refiling it on the same grounds.

Lawyers for Gov. Tom Wolf, a Democrat, said in court filings that Kelly's lawyers never before argued that the U.S. Constitution provides a basis for their claims, making it “highly unlikely” the U.S. Supreme Court will grant what they are seeking.

In the underlying lawsuit, Kelly and the other Republican plaintiffs had sought to either throw out the 2.5 million mail-in ballots submitted under the law or to wipe out the election results and direct the state’s Republican-controlled Legislature to pick Pennsylvania’s presidential electors.

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