WASHINGTON (NYTIMES) - President Donald Trump and his adversaries mobilised on Sunday (Sept 20) for an epic campaign-season showdown over the future of the Supreme Court, even as the nation prepares to honour the life of Justice Ruth Bader Ginsburg in an outdoor viewing to be held according to pandemic-era guidelines.

The President's determination to confirm a replacement for Justice Ginsburg before the Nov 3 election set lawmakers on a collision course with one another at a time when Congress already has major issues on its agenda, including spending Bills to keep the government open past next week and a stalled coronavirus relief package to help millions of Americans left unemployed by the pandemic that has killed nearly 200,000 people in the United States.

Undaunted by the prospect of such a volatile outlook, Mr Trump prepared to announce a nominee as early as Tuesday in hopes of pressuring the Senate to ratify his choice before voters decide whether to give him a second term, and spoke multiple times with Senator Mitch McConnell, the majority leader.

Even as a moderate Republican senator reaffirmed her opposition to such an accelerated timetable on Sunday, others like Senator Lamar Alexander of Tennessee fell in line, and it appeared increasingly likely that Mr Trump may get the votes to proceed, although there were a few holdouts still to be heard from.

The political manoeuvring took place even as the nation was mourning Justice Ginsburg, a champion of women's rights and a hero to the left who died at age 87 last Friday night.

Admirers continued to flock to the Supreme Court building, where they left flowers, candles, signs, newspaper front pages and pictures of the woman who late in life came to be called the Notorious RBG by her fans.

The justice may lie in repose at the court for two days, with a ceremony there as early as Tuesday followed by an outdoor viewing, leaving it unclear whether the President would wait to announce his chosen replacement until afterwards.

Justice Ginsburg's death unleashed a wave of fund-raising by both parties, particularly among liberals, who poured forth US$100 million (S$135 million) through ActBlue, the donation-processing site, by noon on Sunday.

Mr Trump's campaign began selling "Fill That Seat" T-shirts based on a chant at the President's campaign rally last Saturday night.

Former vice-president Joe Biden, the Democratic presidential challenger, on Sunday denounced Mr Trump's decision to move ahead with a nomination and appealed to the handful of moderate Senate Republicans to stop the President from making a lifetime appointment that would shift the balance of power on the nation's highest court without waiting to see the results of the election.

"To jam this nomination through the Senate is just an exercise in raw political power," Mr Biden said in a speech in Philadelphia, noting that Republicans refused to even consider President Barack Obama's nominee after Justice Antonin Scalia died in February 2016, citing the coming election.

"I don't believe the people of this nation will stand for it. President Trump has already made it clear this is about power, pure and simple."

If Mr Trump wins the race, Mr Biden added, then the Senate should consider his choice.

"But if I win the election, President Trump's nomination should be withdrawn," said Mr Biden, who has promised to make his first appointment to the Supreme Court an African American woman to the Supreme Court.

"As the new president, I should be the one who nominates Justice Ginsburg's successor, a nominee who should get a fair hearing in the Senate before a confirmation vote."

A new poll showed that the American public agrees with him and opposes Mr Trump's plan to rush a new justice onto the court.

Of those surveyed by Reuters and Ipsos since Justice Ginsburg's death, 62 per cent said her seat should be filled by the winner of the November election, including the vast majority of Democrats and even half of Republicans.

One reason Mr Trump may feel differently is the possibility that he may not be that winner.

Mr Biden has consistently led the President in polls for months, and a new survey released on Sunday by NBC News and The Wall Street Journal found the Democrat's lead stable at 51 per cent to 43 per cent, essentially unchanged since before the two parties' nominating conventions.

Mr Trump's focus on law and order in recent weeks has not changed the overall dynamics of the race, and nine in 10 of those surveyed said their minds were firmly made up.

The White House hopes that a Supreme Court fight will make a difference when everything until now has not, giving Republican voters who care about the courts, particularly those opposed to legal abortion, a reason to turn out for him despite any concerns about his handling of the coronavirus, the state of the economy or other issues.

"Trump needed a circuit-breaking event to change the dynamic of the race, which has clearly favoured Biden so far," said Mr Douglas Sosnik, who was president Bill Clinton's White House political director during his 1996 re-election campaign.

"Up until now, the election has largely been about the impact of the coronavirus on the health of the public and of the economy, and any day that's the focus is a bad day for Trump."

Mr Trump vowed at his campaign rally on Saturday night to pick a woman, and people informed about the process said on Sunday that he was considering Judge Amy Coney Barrett of the 7th US Circuit Court of Appeals in Chicago, Judge Barbara Lagoa of the 11th Circuit in Atlanta and Ms Kate Todd, a deputy White House counsel.

Judge Barrett, a favourite of conservatives for her staunch opposition to abortion, is considered the favourite, and many Republicans active in court issues would be disappointed if the President picked anyone else.

Judge Lagoa is seen as the second choice, appealing to the President in particular because of her Cuban American heritage and ties to Florida, a must-win state for Mr Trump this autumn.

Ms Todd, who has been helping to manage the judicial nomination process, has admirers in the White House, although she is thought to be a distant third.

Mr Mark Meadows, the White House chief of staff, has also been promoting Judge Allison Jones Rushing of the 4th Circuit in Richmond, Virginia, who was appointed to the bench by Mr Trump just last year and at age 38 is viewed by many as too young, according to the people close to the process.

Mr McConnell has committed to holding a vote on Mr Trump's forthcoming nominee, but not to any particular time frame, and in theory could wait for the lame-duck session after the election.

Mr McConnell plans to meet his leadership team on Monday and with the whole Republican conference on Tuesday.

Senator Lisa Murkowski, an Alaska Republican, confirmed on Sunday what she had said before Justice Ginsburg's death, that she opposed a vote so close to the election.

"I did not support taking up a nomination eight months before the 2016 election to fill the vacancy created by the passing of Justice Scalia," she said.

"We are now even closer to the 2020 election - less than two months out - and I believe the same standard must apply."

But many Republicans who four years ago blocked Judge Merrick Garland, Mr Obama's choice to replace Mr Scalia, indicated that they had no problem going ahead with Mr Trump's selection, saying the difference now was that the President and the Senate majority were from the same party.

"No one should be surprised that a Republican Senate majority would vote on a Republican President's Supreme Court nomination, even during a presidential election year," Mr Alexander said in a statement Sunday.

"The Constitution gives senators the power to do it. The voters who elected them expect it."

"Senator McConnell is only doing what Democrat leaders have said they would do if the shoe were on the other foot," he added.

A number of other Republicans who were seen as possible objectors to a pre-election confirmation have also indicated they will support one, including most prominently Senator Lindsey Graham of South Carolina, chair of the Senate Judiciary Committee, who previously vowed to do the exact opposite if a vacancy occurred in the last year of Mr Trump's term.

Still silent on Sunday, however, were a handful of Republicans who could in theory join Ms Murkowski and Senator Susan Collins of Maine in blocking a quick vote: Senators Mitt Romney of Utah, Cory Gardner of Colorado and Charles Grassley of Iowa.

With a 53-47 majority and Vice-President Mike Pence to break ties, Mr McConnell can afford to lose only one of them.

The average Supreme Court confirmation takes about 70 days from the nomination, and it is not clear how the Senate would proceed with just 42 days as of Tuesday, especially with annual spending Bills and the coronavirus relief package still to be addressed.

House Speaker Nancy Pelosi said on Sunday that Democrats had ways to obstruct the process.

"We have our options," she said on This Week on ABC.

"We have arrows in our quiver that I'm not about to discuss right now, but the fact is we have a big challenge in our country."

But with the new fiscal year starting on Oct 1, Ms Pelosi ruled out holding up spending Bills as leverage.

"There is some enthusiasm among - some exuberance on the left to say, 'Let's use that', but we're not going to be shutting down government," she said.

Since the elimination of the filibuster in Supreme Court nominations, Democrats in the Senate have much less ability to stall or block confirmation.

Some Democrats, frustrated over their lack of influence, have floated what would have normally been considered far-fetched ideas like another impeachment or adding seats to the Supreme Court to offset Trump appointees if they take over the White House and Congress.

Ms Pelosi declined to rule out another impeachment, but it seemed implausible.

For Mr Trump, the confirmation process is likely to be led by Mr Pat Cipollone, the White House counsel, who is known to many in the Senate from his defence of the President during the impeachment trial this year.

Even Senate leaders seemed uncertain how the process would play out.

"This should take as long as it needs to take but no longer," Senator Roy Blunt of Missouri, a member of the Republican leadership, said on Face the Nation on CBS.

"There is plenty of time to get this done. But to get it done before Election Day, everything has to work, I think, pretty precisely."