(Bloomberg) — The U.S. Supreme Court dealt a sharp blow to President Donald Trump’s efforts to overturn the election results, rejecting a request by some of his Republican allies to nullify President-elect Joe Biden’s victory in Pennsylvania.The rebuff came without explanation and with no noted dissents. It marks the first time the full high court has weighed in on efforts by Trump and his supporters to reverse Biden’s victory.The rejection came in a one-sentence order that reflected the participation of the newest justice, Trump appointee Amy Coney Barrett. During her confirmation hearing in October, Democrats had called on Barrett to say whether she would disqualify herself from any Trump-related election litigation.Lawmakers led by U.S. Representative Mike Kelly contended that the Pennsylvania General Assembly exceeded its power by allowing universal mail-in voting for the 2020 election.The Pennsylvania Supreme Court rejected that argument, saying Republicans waited too long to sue and were advocating the “extraordinary proposition that the court disenfranchise all 6.9 million Pennsylvanians who voted in the general election” and throw the decision to the state legislature.Biden would win the presidency even if Republicans had somehow nullified his Pennsylvania victory. Trump still would be at least two states short of securing a majority in the Electoral College, which will formally select the next president on Dec. 14. Biden won 306 electoral votes to Trump’s 232.The order came on the day of an important election milestone for Biden, the so-called safe-harbor deadline. Under federal law, if by Tuesday a state appoints its electors and the loser has had a chance to challenge the results, Congress must consider the electors “conclusive” when it meets in a joint session on Jan. 6 to tally the votes.The order also came hours after Texas filed an equally long-shot Supreme Court bid to reverse Biden’s victories in Pennsylvania, Wisconsin, Georgia and Michigan.The case is Kelly v. Pennsylvania, 20A98.(Updates with Barrett taking part in third paragraph.)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.