Ginsburg’s death, coming just weeks before the election, offers Republicans a chance to lock in a decades-long conservative majority on the court, where justices are appointed for life.

The stakes are high as the decision could affect such life-and-death issues as abortion, health care, gun control and gay rights.

They are pushed even higher in a bitter election year when the justices can play a decisive role in legal wrangling over a contested result – such as when they ruled in George W. Bush’s favour to end the 2000 election debacle.

Trump has already named two justices during his first term as president, Brett Kavanaugh and Neil Gorsuch, giving conservatives a 5-4 majority before Ginsburg’s death, though that does not guarantee rulings in Trump’s favour – there have been several recent examples of conservatives siding with their progressive colleagues.

Trump, who is lagging in the polls behind Democratic opponent Joe Biden, has another powerful incentive to move ahead: providing a jolt of enthusiasm among his anti-abortion and evangelical supporters.

Speaking at a rally in North Carolina later Saturday, he took an impromptu poll from the crowd, asking them to cheer for either a woman or a man to be his pick. The crowd cheered considerably louder for a woman.

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“That’s a very accurate poll because that’s the way I feel,” he said. “It will be a woman. A very talented, very brilliant woman, who I haven’t chosen yet – but we have numerous women on the list.”

Those under close consideration include three women who are federal appeal court judges: Amy Coney Barrett, beloved among conservatives and an early favourite; Barbara Lagoa, who is Hispanic and comes from the battleground state of Florida and Allison Jones Rushing, who clerked for Justice Clarence Thomas and for Gorsuch, when the current Trump-appointed justice was an appeal court judge.

At least one man, appeal court judge Amul Thapar, has also been under consideration. An ally of Senate Majority Leader Mitch McConnell, he has been screened by Trump’s team for past openings and he would be the first Asian-American on the high court.

Ginsburg was one of only three women on the nine-person bench.

But, with less than 45 days to go before the election and some early voting already begun in some states, galvanised Democrats are pushing back furiously.

Biden said on Friday that “the voters should pick the president and the president should pick the justice for the Senate to consider”.

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The prospect of a fierce partisan nomination battle and rushed Senate confirmation vote has ignited his party.

While Democrats’ options seem limited, Senate minority leader Chuck Schumer told party members Saturday that if Republicans press ahead, then “nothing is off the table”, according to media reports.

“This vacancy should not be filled until we have a new president,” Schumer said Friday, carefully echoing the words of Republican Senate majority leader Mitch McConnell in 2016 when he blocked Obama nominee Merrick Garland.

Republicans in theory have the Senate votes to push through a Trump nominee, but they could be blocked by only a handful of defections.

Republican Senator Susan Collins became the first to break ranks when she announced Saturday she would not support a vote on any Trump nominee before the election.

“The decision on a lifetime appointment to the Supreme Court should be made by the president who is elected on November 3,” she said in a statement.

The Maine lawmaker is among a handful of moderate Republican senators – including Lisa Murkowski of Alaska – who have already expressed doubts about a rushed vote.

“I totally disagree with her,” Trump said of Collins’ stance, referring to his 2016 election in adding that “we have an obligation as the winners to pick who we want”.

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One prominent Democratic member of the Senate Judiciary Committee, which will oversee the confirmation hearings, is none other than Senator Kamala Harris, Biden’s running mate, who commanded the spotlight 2018 with her aggressive questioning of Trump court nominee Kavanaugh.

Trump has already named scores of conservatives as federal judges, and Democrats fear a deep and lasting shift in balance at the Supreme Court.

“If he’s allowed to put more conservatives in, this is going to be disastrous for the next 40 to 50 years,” said Gloria Browne-Marshall, a civil rights lawyer, on CNN.

Analysts predicted Democrats would do their best to drag out the process while fanning public outrage.

“Their option is to build a groundswell … to try to convince at least four Republican senators to vote ‘no’ on whoever the president puts forward,” Amy Howe, co-founder of a Supreme Court blog, said on CNN.

Some Democrats have mused that if Biden was elected and Democrats control both houses of Congress, they might expand the court from nine seats to 11 – allowing the new president to appoint two more liberal justices.

Additional reporting by Associated Press