Masterstroke that could give Trump another four years
The stunning appointment of conservative judge Amy Coney Barrett may yet prove to be the masterstroke that gives Donald Trump another four years in the White House.
President Trump has promised to ask the Supreme Court to make a call on the validity of the election.
"We'll be going to the US Supreme Court," he said. "We want all voting to stop."
Commentators in the US said the Trump team will "litigate everything they can get their hands on".
Mr Trump's son Eric said: "The Democrats know that the only way they can win this election is to cheat in Pennsylvania."
University of Pennsylvania Professor Kermit Roosevelt, an expert in constitutional law and conflict of laws, said the election would end up in front of the Supreme Court if mail-in votes were alleged to be invalid.
"There is absolutely no requirement that counting end before the state deadlines, and votes have always been counted past Election Day," Prof Roosevelt said.
"There are arguments, some of which have already been floated and rejected, that various steps states took - either on their own or because of state judicial decisions, to accommodate voters' concerns about coronavirus - violate the constitutional provision that states award their electoral votes in the manner that the state legislature directs. I think we will see litigation about this, unless Biden pulls away far enough that it would be obviously futile."
A recount was demanded in the state of Wisconsin by Team Trump just moments after it was announced Joe Biden had taken a lead of more than 20,000 votes.
"Despite ridiculous public polling used as a voter suppression tactic, Wisconsin has been a razor thin race as we always knew it would be," Trump Campaign Manager Bill Stepien said.
"There have been reports of irregularities in several Wisconsin counties which raise serious doubts about the validity of the results.
"The President is well within the threshold to request a recount and we will immediately do so."
Mr Trump's lawyer Rudy Giuliani said 120,000 ballots "mysteriously appeared" at 4am in favour of Mr Biden.
"They're not gonna steal this election. This election is gonna be decided by the people. We are gonna continue this lawsuit. We are gonna bring a second one and we're gonna bring a federal lawsuit. Sorry, we're gonna fight for the people. President Trump has won Pennsylvania. Do you think we're stupid? Do you think we're fools?"
The Trump campaign also filed a suit in Michigan to halt vote counting there, claiming GOP watchers were denied access to observe the review of ballots.
The campaign is also set to take "critical legal actions in Pennsylvania" to try and "put a stop" to Democrats' "scheming to disenfranchise and dilute Republican votes."
The President's team was also keeping its legal options open to challenge absentee votes in Pennsylvania if the vital swing state was still in play for Donald Trump.
The Supreme Court decides disputes after lower courts have made their own rulings.
While there have been countless election cases filed around the nation, it is not clear which of them might reach the court in the coming days.
But one candidate is already on the court's docket. Last month, the court refused to put a case from Pennsylvania on a fast track, but three justices indicated that the court might return to it later if need be.
On Wednesday afternoon, the Trump campaign applied to the Supreme Court for permission to participate in the case alongside Republican state politicians and the Republican Party of Pennsylvania.
The court has not said whether it would hear the case or when it might decide whether to grant review.
The Biden camp said it had the absentee ballots to clinch the 270 electoral votes needed to win, but Trump and his surrogates suggested these were fraudulent "ballot dumps".
The campaigns are gearing up for a costly legal battle, with the president promising to challenge Biden's claimed victory in Wisconsin and his lawyers saying they would possibly launch federal action.
Originally published as Masterstroke that could give Trump another four years