Seventeen states whose elections were won by President Donald Trump told the Supreme Court on Wednesday that they support Texas Attorney General Ken Paxton's bid to file a lawsuit that could effectively reverse President-elect Joe Biden's projected Electoral College victory.
The filing backing Paxton by those states came a day after he asked the Supreme Court for permission to sue Georgia, Michigan, Pennsylvania and Wisconsin, all of which Biden won, over their voting processes.
Later Wednesday, Trump filed a motion to intervene in the case "in his personal capacity" as a presidential candidate. The Supreme Court has yet to rule on Paxton's request.
The states supporting the suit, all of which have Republican attorneys general, are Missouri, Alabama, Arkansas, Florida, Indiana, Kansas, Louisiana, Mississippi, Montana, Nebraska, North Dakota, Oklahoma, South Carolina, South Dakota, Tennessee, Utah and West Virginia.
Trump defeated Biden in the popular vote in all of those states, though one of Nebraska's electoral votes was awarded to Biden.
Representatives for the four battleground states being targeted in the lawsuit did not immediately respond to CNBC's requests for comment.
After Trump asked to intervene in the case, 17 former officials and lawmakers filed their own brief supporting the four swing states. They argued Paxton's case does not belong in the Supreme Court, suggesting his claims could be made elsewhere.
"The Constitution does not make this Court the multidistrict litigation panel for trials of presidential election disputes," the brief said.
The court filing was signed by former officials who had worked in Republican administrations, as well as multiple former members of the House and Senate.
Paxton's case makes "a mockery of federalism and separation of powers," their brief said.
"It would violate the most fundamental constitutional principles for this Court to serve as the trial court for presidential election disputes."
Paxton, a Republican who remains under indictment for state felony securities fraud charges, is asking the high court for permission to sue the four states to block their certification of Biden's wins in them.
Paxton argues that a block is warranted because of supposedly improper changes to voting procedures there in the past year, purportedly different treatment of voters in Democratic-heavy areas, and voting "irregularities."
The four swing-state defendants are set to file their replies in opposition to Paxton's requests of the court by 3 p.m. on Thursday.
The effort comes as all states have certified their individual presidential election results, which show that Biden easily won the national popular vote.
Biden is projected to win the Electoral College when it meets Monday with 36 more votes than the 270-vote minimum needed to clinch the White House.
Michigan Attorney General Dana Nessel on Tuesday said Paxton's filing "is a publicity stunt, not a serious legal pleading."
"The erosion of confidence in our democratic system isn't attributable to the good people of Michigan, Wisconsin, Georgia or Pennsylvania but rather to partisan officials, like Mr. Paxton, who place loyalty to a person over loyalty to their country," Nessel said in a statement.
"The Michigan issues raised in this complaint have already been thoroughly litigated and roundly rejected in both state and federal courts – by judges appointed from both political parties. Mr. Paxton's actions are beneath the dignity of the office of Attorney General and the people of the great state of Texas."
Trump has refused to concede the election to Biden, claiming without evidence that he was the victim of widespread ballot fraud.
Trump and his campaign, as well as their political allies, have repeatedly failed in their legal attempts to invalidate votes for Biden.
The Supreme Court on Tuesday declined to hear a separate bid from Trump-allied Republicans challenging Biden's win in Pennsylvania.
Election law experts saw that apparently unanimous rejection as a signal that the remaining efforts to overturn Biden's win were all but doomed at the Supreme Court.
But the GOP plaintiffs in that case plan to petition the high court for a formal appeal, The Hill reported Wednesday.
The president and his lawyer, Rudy Giuliani, recently have pushed for legislatures in battleground states whose popular elections were won by Biden to overrule their citizens, and to appoint a slate of electors for Trump to the Electoral College.