On Tuesday, Texas filed a lawsuit seeking to block the states of Georgia, Michigan, Pennsylvania and Wisconsin from participating in the Electoral College.
"The Court should not abide this seditious abuse of the judicial process, and should send a clear and unmistakable signal that such abuse must never be replicated," the battleground states said in a brief in response to the Texas lawsuit.
On Wednesday, 17 Republican states submitted a brief to the US Supreme Court in support of Texas' lawsuit as "amici curiae" - without formally joining the bid.
The Donald Trump legal team's lawyer filed a motion asking the Supreme Court to allow the president to join the Texas case, in order to "protect his unique and substantial personal interests as a candidate for re-election to the Office of President in the 3 November 2020 election". Trump’s lawyer also filed a Bill of Complaint outlining additional issues, including the lack of signature verification in Georgia, which were not mentioned in the Texas lawsuit.
Several of the states sued by Texas have said they did not find evidence of widespread fraud or substantial irregularities. The Trump campaign and the Republican Party have lost more than 50 legal battles to try to invalidate President-elect Joe Biden's victory in key swing states.