This is part of a major series called Advancing Australia, in which leading academics examine the key issues facing Australia in the lead-up to the 2019 federal election and beyond. Read the other pieces in the series here.

Long before the Turnbull government failed to land its climate-energy policy, the new Liberal prime minister had signalled his reluctance to pursue progressive causes, voluntarily garaging the republican campaign bus he had so famously driven.

Reasonably or not, the hopes of millions of Australian republicans had spiked when Malcolm Turnbull replaced the conservative monarchist Tony Abbott in September 2015.

Yet those hopes would quickly be dashed, as the erstwhile face of the Australian Republican Movement turned Liberal prime minister would relegate constitutional self-determination to third-order status. In the process, he depicted himself – only half tongue-in-cheek – as a modern “Elizabethan”.

Read more: A model for an Australian republic that can unite republicans and win a referendum

In the blink of an eye (or was it a royal wave?), republican ambitions returned to Labor’s Bill Shorten. They were no doubt sobered by the thought of further delays and the grim reality that the fleeting alignment of a republican prime minister and a republican opposition leader had still produced nothing.

But if Shorten becomes prime minister in 2019, will he drive the case for an Australian head of state forward? More fundamentally, can the feted republic even come to pass in the absence of muscular support from both hemispheres of politics?

A history of disappointments

Self-evidently, it is a difficult project burdened with overblown hopes, largely intangible benefits and commensurate disappointments. Reversals have been costly.

Well might Turnbull have described John Howard as the “prime minister who broke this nation’s heart” after the 1999 referendum defeat, because it would be a hardness in his own heart that would lead him to dismiss a republic while Queen Elizabeth II remained on the throne.

And Turnbull would go further, essentially telling voters it no longer mattered anyway. In January 2016, just months into his prime ministership, he said:

There are many more urgent issues confronting Australia, and indeed confronting the government, than the momentum or the desire for Australia to become a republic. No politician, no prime minister or opposition leader or premier, can make Australia a republic - only the Australian people can do that through a referendum.

Presumably, this statement of the obvious served to remind proponents that, in matters of constitutional change, even starting with majority public support is merely that – a start.

It’s no revelation that constitutional reform is supremely difficult in Australia, given the need to secure a so-called “double majority”. This means a majority of votes nationwide plus a majority in at least four of the six states.

But withdraw the crucial ingredient of governmental leadership and that degree of difficulty switches to impossible.

Shorten’s two-step strategy

This is why Shorten wants to build support in stages. He has pledged to put the case to Australians “in principle” first via an indicative first-term plebiscite. The would be followed by a formal referendum, probably held over to a second term.

Typically reserved, Abbott branded this “completely toxic”. He argued it would “delegitimise the constitution we have without putting anything in its place”.

Some republicans had favoured this in 1999, but Howard saw the danger to the Crown’s authority arising from any popular republican mandate and the reform momentum it might generate.

So he determined to make an ally of the higher bar for success required by referendum, along with the divisions emerging in the republican camp between minimalists and direct electionists.

Perversely, Shorten’s two-stage approach has a more contemporaneous justification in the form of the calamitous 2016 Brexit referendum in Britain.

For all that country’s post-ballot dysfunction, Brexit graphically demonstrates the power of an initial yes or no choice when clearly expressed as an abstract principle. That is, when it is separated from the thornier and potentially deal-breaking details to be faced subsequently.

Few doubt that had Britons been fully apprised of the extraordinary extent of the changes and the enormous economic costs of withdrawing from the European Union, many more would have voted to remain.

However, a simple yes or no question is not the position of the Australian Republican Movement. Its national director, Michael Cooney, told a Museum of Australian Democracy forum in February 2019 that it favours a double-barrelled approach first up.

This would ask voters if they want an Australian head of state, and then how they would like that person to be chosen.

This is based on the group’s social research, which shows support for a directly elected president is as high as 75% among republicans. But that support trails away quickly if the head of state is to be chosen by the parliament – a model pilloried by many as a so-called “politician’s republic”.

That division, with its echoes of the unsuccessful push in 1999, underlines just how fragile the support for a republic is, and just how easily it can crumble when the details are considered.

A question of constitutional priorities

In any event, there are concerns that even a Labor government could delay the plebiscite, for fear of compromising a separate push for constitutional recognition of Indigenous Australians.

Read more: First reconciliation, then a republic – starting with changing the date of Australia Day

Few republicans would begrudge First Australians that priority, notwithstanding that agreement is yet to be reached on the precise form so-called “Con-Rec” would take.

Labor insiders say Shorten remains committed to the republic plebiscite in his first term, if elected, but will ensure that Con-Rec is prioritised. As one put it: