CANBERRA, Australia (AP) — Both candidates vying to become Australia's prime minister in Saturday's elections are promising to stay in the job for the entire three-year term and shut the revolving door to high office.

Lasting the distance between elections was once a prime minister's pledge that Australian voters didn't need to question. But since an extraordinary period of political instability began a decade ago, four prime ministers have been dumped by their own parties and only one has been ousted by voters.

If the winner in the race between incumbent Prime Minister Scott Morrison and opposition leader Bill Shorten keeps his promise to last three years, he will become the first to survive a single term since Prime Minister John Howard lost his Sydney seat in 2007 elections.