Sudden Supreme Court vacancy seizes US campaign spotlight

The US Supreme Court's future grabbed centre stage in the country's presidential campaign with the sudden death of Justice Antonin Scalia, setting up an election-year battle over who should succeed him on a nine-member bench that interprets US law over such hot-button issues as abortion, gay marriage, healthcare and immigration.

The death of the 79-year-old conservative justice, announced by Chief Justice John Roberts, set up a political showdown between President Barack Obama, a Democrat, and the Republican-controlled Senate over who will replace Scalia and drew swift and furious comment from candidates vying to be elected president in November.

The US president has the job of nominating justices, and the Senate has the job of confirming. Senate Majority Leader Mitch McConnell, whose Republicans control the Senate, issued a statement saying the vacancy should not be filled until Obama's successor takes office next January so that voters can have a say in the selection.

Both political parties already had made the future of the country's highest court a campaign issue even though it usually fails to resonate with voters and rarely ranks as a top issue in public opinion polls.

Debating the court allows both Democrats and Republicans to argue policy planks that are central to their message.

Democratic presidential hopeful Hillary Clinton often speaks at campaign rallies about the recent decisions of the court, such as legalizing gay marriage, and how a Republican president might name justices who could undo that decision.

Her Democratic rival, Bernie Sanders, often rails against the 2010 Citizens United decision, which legalized unlimited campaign spending by individuals and corporations.

Democrats would likely be pleased to see Obama name a replacement, which would tip the balance of the nine-member court in favour of liberals after several years favouring conservatives by a 5-4 majority.

Despite the court's conservative credentials, Republicans have been highly critical, telling voters that a Republican president is needed to name jurists who will overturn such decisions as Roe vs Wade in 1973 legalizing abortion and one in 2015 legalizing same-sex marriage along with two decisions upholding aspects of Obama's 2010 signature healthcare law.

Some of the Republican White House hopefuls were quick to say Obama should not appoint Scalia's successor.

US Senator Ted Cruz of Texas praised Scalia as a "stalwart defender of the Constitution." "Justice Scalia was an American hero," Cruz wrote on the social media website Twitter. "We owe it to him, & the Nation, for the Senate to ensure that the next President names his replacement." Florida Senator Marco Rubio echoed Cruz. "The next president must nominate a justice who will continue Justice Scalia's unwavering belief in the founding principles that we hold dear," Rubio said in a statement.