Biden’s statement is false as regards the Supreme Court, which never heard about any “cause” or “evidence,” but simply declined to hear the challenges brought by Republicans. It declined, for instance, to hear an appeal from a Pennsylvania Supreme Court case that rejected a challenge to the state’s vote-by-mail law; and it also declined to hear a challenge that Texas filed against election law changes in Pennsylvania and three other states, saying that Texas lacked standing to sue.
Rightly or wrongly, the Supreme Court stayed out of the 2020 election — perhaps fearing the political fallout were it to intervene, as it did in Bush v. Gore (2000), a case that caused Democrats to accelerate their attacks on the judiciary.
Biden’s claim that the election was “the most scrutinized election ever in American history” also misses the point. The election laws were changed, in the middle of the campaign, to allow mass vote by mail — at the behest of Democrats, and over the objections of Republicans. The rate of rejection of absentee ballots dropped dramatically from the primary to the general election, despite millions more ballots being delivered by mail. And private money from left-wing billionaires such as Mark Zuckerberg was used to fund local vote by mail efforts in Democratic counties in key battleground states.
Republican challenges were not only about claims of election fraud, but about the legitimacy and constitutionality of changes that legalized voting practices that until recently were considered vulnerable to fraud and partisan manipulation.