US President Donald Trump has confirmed he will seek to replace Supreme Court Justice Ruth Bader Ginsburg "without delay", setting up a monumental political fight on the cusp of the presidential election.
Justice Ginsberg, an icon of progressive law, died at the age of 87 yesterday after a long battle with pancreatic cancer.
Her dying wish, revealed by her granddaughter Clara Spera, was that she "not be replaced until a new president is installed".
But today, Trump indicated he would push ahead with the nomination process immediately. He plans to name Justice Ginsberg's potential successor next week.
"We were put in this position of power and importance to make decisions for the people who so proudly elected us, the most important of which has long been considered to be the selection of United States Supreme Court justices," the President tweeted.
"We have this obligation, without delay!"
Under America's judicial system, the President nominates Justices, and the Senate confirms them. Each Justice is appointed for life.
Should Trump succeed in replacing Justice Ginsberg with a conservative jurist, the balance of the court will shift decisively.
Before her death, there were four liberals and five conservatives – but one of the conservatives, Chief Justice John Roberts, acted as more of a swing vote. The balance could now change to three liberals and six conservatives.
Democrats worry that could lead to the court overturning Roe vs Wade, a landmark decision from 1973 which effectively legalised abortion in the United States.
Further complicating the political debate is Senate Republicans' actions four years ago, when they refused to consider a Supreme Court nominee put forward by then-president Barack Obama because it was an election year.
The conservative Justice Antonin Scalia died in February of 2016, about nine months before the presidential election. Obama nominated Judge Merrick Garland to replace him. But Senate Leader Mitch McConnell refused to even hold hearings, let alone a vote.
"The American people should have a voice in the selection of their next Supreme Court Justice. Therefore, this vacancy should not be filled until we have a new president," McConnell said at the time.
Trump went on to win the election, and after taking office he filled the vacant seat with a conservative Justice, Neil Gorsuch.
That was followed by his appointment of another conservative, Brett Kavanaugh, in 2018.
Justice Ginsberg's death came just 46 days before this year's election, which is happening on November 3. This time, however, McConnell is keen to press ahead.
"Americans re-elected our (Senate) majority in 2016 and expanded it in 2018 because we pledged to work with President Trump and support his agenda, particularly his outstanding appointments to the federal judiciary. Once again, we will keep our promise," he said.
"President Trump's nominee will receive a vote on the floor of the United States Senate."
The Democrats, and many of the President's critics in the media, have been quick to angrily accuse the Republicans of hypocrisy.
"Four and a half years ago, when Republicans refused to hold a hearing or an up-or-down vote on Merrick Garland, they invented the principle that the Senate shouldn't fill an open seat on the Supreme Court before a new president was sworn in," said Obama.
"A basic principle of the law, and of everyday fairness, is that we apply rules with consistency and not based on what's convenient or advantageous in the moment.
"Republican senators are now called to apply that standard."
The Republicans hold a 53-47 majority in the Senate, and in the event of a tie, Vice President Mike Pence gets to cast the deciding vote. So for Trump's attempt to fail, four Republican senators will need to vote against his nominee.
So far, only two have expressed opposition to replacing Justice Ginsberg before the election.
"In order for the American people to have faith in their elected officials, we must act fairly and consistently, no matter which political party is in power," Maine Senator Susan Collins said today.
"I do not believe that the Senate should vote on the nominee prior to the election. In fairness to the American people, who will either be re-electing the President or selecting a new one, the decision on a lifetime appointment to the Supreme Court should be made by the president who is elected on November 3."
Alaska Senator Lisa Murkowski is also opposed to McConnell's move.
"I would not vote to confirm a Supreme Court nominee. We are 50 some days away from an election," she said.
Democrats are also closely watching Utah Senator Mitt Romney, the 2012 Republican presidential nominee, who was notably the only Republican to vote in favour of removing Trump from office during his impeachment trial earlier this year.
Other Republican senators who have previously expressed opposition to choosing a Supreme Court Justice in an election year include Chuck Grassley, Ted Cruz and Lindsey Graham. All of them now support replacing Justice Ginsberg immediately.
Reporters asked Trump about Ms Collins' stance during a brief media conference today.
"I totally disagree with her," he said.
"We have an obligation. We won, and we have an obligation as the winners to pick who we want. That's not the next president."
"We're here now. Right now, we're here. And we have an obligation to the voters, all of the people, the millions of people that put us here in the form of a victory.
"So I would disagree."
Judge Amy Coney Barrett is widely seen as a frontrunner to be nominated by Trump. Asked about her, he confirmed he would likely choose a woman.
"I could see, most likely, it would be a woman. Yeah, I think I can say that it would be a woman," Trump said.
"I would say that a woman would be in first place, yes. The choice of a woman I would say would certainly be appropriate.
"We're working with all of the Republican senators and working with Mitch McConnell, and we'll be making a decision. I would think before (the election) would be very good, but we'll be making a decision.
"I think the process can go very, very fast. I'll be making my choice soon, and when the choice is made, I'll be sending it over to Mitch and the Senate, and they will do what they have to do.
"I think we'll have a very popular choice, whoever it may be."