Bid to stop gay marriage survey goes to Australia's top court
Gay rights advocates have gone to Australia's highest court in an attempt to prevent the government from asking the public whether same-sex marriage should be legalised.
The campaigners want parliament to decide the issue without public consultation and are arguing in the High Court that the government does not have the constitutional power to start the postal survey next week.
Opinion polls show most Australians want same-sex marriage legalised, but many supporters question how representative of national attitudes the survey would be.
The seven judges will hear two similar cases simultaneously over Tuesday and Wednesday in Melbourne.
They could rule on the validity of the survey as early as Wednesday and prevent ballots being posted to voters from September 12.
One case is brought by independent MP Andrew Wilkie and gay rights campaigners Felicity Marlowe and Shelley Argent.
Ms Argent has described the survey as a "demeaning, hate-filled and pointless vote that will go nowhere and resolve nothing".
The second case is brought by Janet Rice, a senator in the minor Greens party who is married to a transgender partner with a male birth certificate, and the Australian Marriage Equality lobby group.
The survey is the second choice of prime minister Malcolm Turnbull's conservative government that had promised a rare, compulsory vote known as a plebiscite.
But the Senate refused to approve the 170 million Australian dollars (£105m) that the vote on November 25 would have cost.
Instead, the government is pushing for a 122 million-dollar unique, voluntary postal vote without Senate approval.
If a majority want marriage equality, parliament would be allowed to decide the issue by December. But some MPs have said their votes would not be swayed by public opinion, raising questions about why the public is being surveyed.
Mr Wilkie's case is that the government's power to fund the vote without Senate approval can only be used in unforeseen emergencies and not in the ordinary business of government.
Even if the government could fund the vote, Mr Wilkie argues that it could not make the Australian Bureau of Statistics carry it out.
While the bureau has the power to obtain statistical data from the Australian population, gathering opinions is different, he argues.
Despite the legal cloud hanging over the postal survey, acrimonious campaigns on both sides of the argument are gathering pace.
Mr Turnbull and opposition leader Bill Shorten support gay marriage but Mr Turnbull's predecessor and party rival Tony Abbott is a vocal opponent.
Mr Abbott has described a vote against gay marriage as a vote against political correctness.
Many Yes vote supporters including Ms Rice, the litigant, argue that marriage equality is, as the US Supreme Court found, a human right that should not be subjected to an opinion poll.