Explainer: What the timing of Ruth Bader Ginsburg's death means for the US election, and beyond.

US Supreme Court justice Ruth Bader Ginsburg was a giant. A brilliant legal mind, a champion of gender equality, a cultural icon.

The 87-year-old's death overnight of cancer has seen news outlets stacked with tributes and social media inundated with messages of mourning. 

But as admirers lay wreaths and light candles on the steps of the US Supreme Court, roughly three kilometres away, in the bowels of the White House, plans are already being hatched for her replacement.

Who fills the seat, and when, not only has the power to influence the upcoming election but to shape the United States on key issues for decades to come.

Let's take a look at why.

The US Supreme Court: a super simple guide.

The Supreme Court is the highest court in the United States; essentially, the equivalent of the High Court here in Australia. 

As well as being the final stop for Americans seeking justice, the court also has a crucial authority to strike down state laws that are found to be in violation of the US Constitution. In this capacity it has ruled on hugely consequential issues like abortion, same-sex marriage and universal healthcare.

The Supreme Court bench consists of one Chief Justice and eight Associate Justices. That number has varied throughout history (Congress has the power to pass laws changing it), but it's been fixed at nine since 1869.

When a seat becomes vacant, a replacement is appointed by the US President. That nominee must then be confirmed by Senate vote following a series of hearings. In the case of President Trump's most recent pick, Justice Brett Kavanaugh, that process took three months.

Once a justice is confirmed, they hold the position for life (or as long as they choose). That's partly why the opportunity to fill a vacant seat presents such a significant opportunity for a sitting government.

Why R.B.G.'s vacant seat is so important.

The seat left vacant by Ruth Bader Ginsburg's death comes strikingly close to the presidential election: just six weeks out, in fact.

The late Justice R.B.G. Image: Getty. 

It seems unlikely that President Donald Trump will be able to move quickly enough to have his nominee confirmed before then. 

But even if the Democrats wrestle back control of the Senate come November 3, that Senate won't be sworn in until January. 

That means Trump and Republican Senate leader Mitch McConnell could work to fill the Supreme Court seat during this post-election "lame duck" session, leaving Joe Biden to inherit a bench stacked six-to-three with conservative-government picks. 

It's a crucial moment. One that could shape America's stance on hugely important issues (immigration, presidential powers, tax, healthcare and so on) for decades to come. Americans are keenly aware of this, which is why it has the potential to be vote-winning for Trump.

Conservative voters alienated by his handling of the coronavirus pandemic may be enticed back into the fold by the prospect of a Supreme Court that appears, at least, more likely to rule in line with their ideology.

America is home to a large swathe of evangelical Christians who are eager to see the overturn of Roe vs Wade, for example. The landmark 1973 Supreme Court ruling struck down a Texas statute banning abortion and effectively legalised the procedure across the country, but decades on, it remains a hot-button political issue.

Bader Ginsburg was clearly eager to avoid her vacant seat becoming a campaign tool.

She told her granddaughter prior to her death, "My most fervent wish is that I will not be replaced until a new president is installed."

But McConnell today signalled his intention to press ahead: "President Trump's nominee will receive a vote on the floor of the United States Senate," he said in a statement.

Brace yourselves, folks. This is going to be tense.

Feature Image: Getty.