The fact it was even raised highlights the dearth of leadership options within the government, but the mocking response of the Opposition also indicates some concern from that side of the fence.

But political comebacks rarely work in Australia and Costello has already passed up his chance to lead the Liberals.

If we are to hypothesise, though, the question must be asked: Just where would Peter Costello stand in politics today?

What Australian politics over the past 40 or 50 years has shown us is that we like our conservative leaders to be conservative and our progressive leaders to be moderates.

John Howard became Australia’s second longest-serving prime minister by retaining a strict adherence to his conservative roots.

And even Tony Abbott defied his critics by almost winning the 2010 election despite the Coalition starting the campaign 10 points behind Labor in the polls, and then becoming PM in 2013 when those same critics continued to say it could never happen.

Howard and Abbott succeeded by sticking to the Right and  what they believed in rather than trying to impress those who would never vote for them anyway.

Liberal leaders who have courted the centre of Australian politics – Turnbull, Gorton, Peacock and Hewson, among them – have not fared as well at the polls. They might be Labor voters’ favourite Liberal leaders, but there were no votes for them in winning those trophies. 

By contrast, Australia’s most popular prime minister, Bob Hawke, could only take that mantle after severing his links to the policies and practices of the union movement that originally made him a household name. But the greatest lion of the Left, Gough Whitlam, remains a hero in the party despite being a failure as prime minister as his reform agenda moved too quickly for most Australians..

So where does that leave Costello? On the one hand, he is a favourite son of diehard Liberals for the role he played in supporting Howard as they led Australia through some boom economic times.

On the other hand, he also has the grudging respect of Labor voters who support his stance on the referendum and social issues.

Sadly, the question will never be answered at the polls.