At a recent rally of Donald Trump supporters in North Carolina, Republican vice-presidential candidate Mike Pence said the result of the November presidential election would determine the shape of the US Supreme Court for the next 40 years.

Pence’s words were not just overblown political rhetoric. The next president will have a unique opportunity to mould the Supreme Court bench.

The age of the justices is the key reason. For the past 65 years, the average age of retirement for Supreme Court justices has been 78. With three current justices 78 or older and one seat on the court vacant, the next president may end up nominating four justices in their first term.

The current court    

Article 3, Section 1 of the US Constitution provides Supreme Court justices:

… shall hold their offices during good behaviour.

In short, justices are appointed for life or until such time as they choose to retire.

The three justices nudging (or over) 80 include two of the acknowledged liberals, Ruth Bader Ginsburg and Stephen Breyer – both of whom were appointed by Bill Clinton.

They, along with Sonia Sotomayor and Elena Kagan (both nominated by Barack Obama), constitute the liberal wing of the bench. As liberals, they have favoured lifting restrictions on access to abortion, limiting the scope of police power to search, and affirmative action.

Although nominated to the Supreme Court by Republican president Ronald Reagan, Anthony Kennedy, who turned 80 in July, is known as the swing justice.

In close decisions, Kennedy’s vote has often been the deciding one. For instance, he authored the majority opinion (5-4) in the 2015 case that affirmed the right to same-sex marriage. As expected, the four liberal justices joined his decision.

The remaining three justices – John Roberts, Clarence Thomas and Samuel Alito – are acknowledged conservatives. George H.W. Bush nominated Thomas, while his son nominated Alito and Roberts.

None of the three are likely to retire in the near future. If, however, the winner of November’s presidential election secures a second term in 2020, then there is a distinct possibility that one or more of the conservative justices may retire.

Therefore, if the next president serves two terms, they may end up replacing almost the entire Supreme Court bench. No president since Franklin Roosevelt, who appointed eight justices from the late 1930s into the early 1940s, has enjoyed such a privilege. The last president to nominate more than three justices was Dwight Eisenhower, who nominated four between 1955 and 1958.

In addition to the possible retirements, the Supreme Court is still one justice down. Antonin Scalia died suddenly in February 2016. Obama moved swiftly to nominate a replacement for Scalia. He chose Merrick Garland, chief justice of the Washington DC Circuit Court.

But the Republican-controlled Senate Judiciary Committee has refused to call nomination hearings for Garland. The responsibility of filling Scalia’s vacant seat, argue the Republicans, belongs to the next president, not to Obama.

The presidential election will not be the only election to determine the future shape of the Supreme Court. The Senate Judiciary Committee, and then the Senate, votes on and confirms nominees to the court. Even if Hillary Clinton wins the presidency, her right to shape the Supreme Court is not assured. If the Republicans maintain control of the Senate, future nominations face the possibility of being deadlocked or delayed.

The Supreme Court and the election

Convention dictates the justices remain non-partisan, removed from the fray of contemporary politics. Their role is to act as a check on both the executive and the legislature to ensure politics does not prompt government to overstep constitutional authority.

But as the current court has shown, justices tend to vote in line with the political leanings of the president who appointed them. This is hardly a surprise. Presidents nominate well-qualified candidates, but they also pick those likely to support their legislative and political agendas.

This election has signalled a departure from tradition. In May, Ginsburg publicly lambasted Trump. In doing so, she broke with convention, which dictates that Supreme Court justices do not comment on current politics – particularly presidential candidates.

In June, Trump responded with an unusual move of his own, releasing a list of 11 potential nominees to the court. As expected, all are conservative. All are white.

These recent actions signal the extent to which the court itself and the presidential candidates realise what’s at stake this election. Over the next four years, the Supreme Court is likely to hear cases relating to voting rights, freedom of religion, gun control and abortion rights. The next president will play an important role in determining who gets to hear those cases.

Speaking to the crowd in North Carolina, Pence warned a Clinton Supreme Court would use “unaccountable power to make unconstitutional decisions”. His words were an eerie echo of claims made by white southern Democrats in the 1950s as they pushed back against the historic Supreme Court decision that desegregated public schools in 1954.

For the Supreme Court, the stakes in this election are high. The future of justice in the US hinges on the outcome of November’s vote.

Felicity Turner, Assistant Professor of History, Armstrong State University. This article was originally published on The Conversation. Read the original article.

Felicity Turner received her PhD in History from Duke University, North Carolina in 2010. Since 2013, Felicity has been an Assistant Professor of History at Armstrong State University in Savannah, Georgia.