Australians are primed to vote on whether to recognise same-sex marriage. Survey forms will be sent to 16 million people from next week, and campaigning has begun in earnest. Despite this, the High Court may bring the postal survey to an immediate halt. This would be a first, with no other national poll stopped in its tracks in this way. But then again, no past government has sought to hold a national vote in such legally dubious circumstances.

The High Court is doing everything it can to resolve the matter as quickly as possible. It will hear argument today and tomorrow in unfamiliar surroundings. The discovery of asbestos in its building in Canberra means that the case will be heard in a cramped and makeshift Melbourne courtroom. The court will likely announce the result this week given the urgency of the situation.

It is surprising that matters have come to this. The normal path of making law about marriage is a simple vote of Parliament. Instead, conservatives have promoted a more radical option that clashes with Australia's traditions of parliamentary democracy. The non-binding, non-compulsory process run by the Australian Bureau of Statistics is unique in Australian history.

The vote is also constitutionally adventurous because it has twice been rejected by Parliament. This leaves the government open to the attack that it lacks the legal authority to conduct the survey. Nothing in the submissions put by the Commonwealth to the High Court alters my view that the survey will more likely than not be struck down.