Leading article: Ms Gillard's electoral gamble

Australians go to the polls on Saturday for an election called by the Prime Minister, Julia Gillard, just two weeks after she toppled Kevin Rudd. In one way, her decision to go to the country so soon was admirable – for Britons, it underlines the opportunity missed by Gordon Brown during his honeymoon after Tony Blair's resignation. But it also reflected the same opportunistic ruthlessness Ms Gillard showed in her successful challenge to Mr Rudd. She seized the propitious moment, hoping to win a mandate for herself.

As the campaign has sped on, however, it has become less certain that she will succeed. Latest polls suggest the barest majority for Labor, but the almost equal possibility of defeat or a hung Parliament. This is a thrilling contest that is being fought to the wire in typically forthright and rambunctious Australian fashion.

The contentious background to this election may help to explain why climate change, a central issue at the last election and one of the most pressing issues facing the country, has hardly featured. It has not gone away; far from it. As we report today, one of Australia's most important food-producing regions, the Murray-Darling basin, is in the grip of a disastrous drought. Over-use is one reason, and a government scheme entails buying back farmers' irrigation licences in the hope of relieving pressure on the river. But the longer-term cause is climate change, whose effects are more advanced in Australia than almost anywhere else.

The measures proposed by Labor under Mr Rudd, which included an emissions trading scheme, helped the party to power in 2007. But he retreated, in a decision that hastened his fall in the polls, and the most Ms Gillard has offered is a "citizens' assembly" to gauge support. Even this timid initiative is more than her opponent, Tony Abbott, is offering.

Climate change is the signal absentee from this election campaign, but so, to a lesser extent – and to Labor's disadvantage – is the economy. This may be because Australia has weathered the global economic storms of recent years conspicuously well; voters assume the country's good fortune will continue. But it is also because the drama of Ms Gillard's coup is so fresh in the memory that it became an election issue in itself. This – and the old stand-by, immigration – have so far dominated the campaign. Ms Gillard wants to use the final days of campaigning to yank the discussion on to the economy. Her success, or not, could well determine whether her gamble in calling this election pays off.