If Dutton had defeated Turnbull, could the governor-general have stopped him becoming prime minister?

Who decides who is to be prime minister?

When Malcom Turnbull was challenged by Peter Dutton in August 2018 for the leadership of the Liberal Party, and ultimately the prime ministership, Turnbull apparently asserted that the governor-general would not appoint a person whose eligibility to hold the office was in doubt.

Read more: Explainer: is Peter Dutton ineligible to sit in parliament?

His attorney-general, Christian Porter, reportedly replied that Turnbull was “wrong in law” and that the governor-general could only have regard to issues of confidence.

Who was right, and what might have happened if Dutton had been chosen as leader of the Liberal Party?

Not a choice between Dutton and Turnbull

The governor-general can only act to fill a vacancy in the prime ministership if there is one. If Dutton had defeated Turnbull in a leadership challenge, this would not itself have vacated the office of prime minister. Turnbull would have continued as prime minister until he resigned (or in extreme circumstances, was dismissed). So the governor-general would not have faced the question of whether or not to appoint Dutton as prime minister until Turnbull had indicated he was going to resign.

The choice would then have been between Dutton and whoever else the governor-general considered was most likely to hold the confidence of the house. It would be unlikely that the governor-general would seek to reappoint the prime minister who had just resigned, unless he was the only person who could hold the confidence of the lower house.

This would seem most unlikely in the circumstances.

What if Turnbull had advised the governor-general to appoint someone else?

The more plausible scenario would have been that Turnbull resigned as prime minister but advised the governor-general to appoint someone other than Dutton, such as Julie Bishop, due to concerns about Dutton’s possible disqualification under section 44 of the Constitution. This raises the question of whether the advice of an outgoing prime minister about who should be his or her successor is conventionally binding on the governor-general.

Ordinarily, the principle of responsible government requires the governor-general to act on the advice of ministers who are responsible for that advice to parliament, and through parliament to the people.

But that principle only works when the minister continues to be responsible for that advice. An outgoing prime minister necessarily ceases to be responsible to parliament for advice about his or her successor. The governor-general is instead obliged, by convention, to appoint as prime minister the person who is most likely to command the confidence of the lower house, regardless of what the outgoing prime minister advises.

While this is the orthodox constitutional position, there is still some controversy about it. When Kevin Rudd defeated Julia Gillard for the leadership of the Labor Party in 2013, it was not clear whether the crossbenchers who supported the minority Gillard government would support Rudd.

The then governor-general, Quentin Bryce, sought advice from the acting solicitor-general as to whether to appoint Rudd as prime minister on the basis of Gillard’s advice. The acting solicitor-general advised that the governor-general should do so, and appeared to take the view that the outgoing prime minister’s advice was conventionally binding.

He did not advise the governor-general that her sole consideration should be who held the confidence of the house.

Who advises the governor-general on legal issues?

If, in 2018, the governor-general had sought legal advice about his powers and the conventions that govern them, two questions would have arisen. First, who should provide the advice? Should it be the solicitor-general, the attorney-general, or the even the prime minister?

In 1975, when the governor-general asked for legal advice, the prime minister, Gough Whitlam, said it could only come through him. The attorney-general and the solicitor-general prepared a joint draft advice, but it was not provided promptly.

When a frustrated governor-general, Sir John Kerr, called in the attorney-general to get the advice, he was presented with a draft that the attorney-general apparently said he had not carefully read and did not necessarily reflect his views. Kerr later, controversially, sought the advice of the chief justice, Sir Garfield Barwick.

In more recent times, the solicitor-general has provided advice to the governor-general, as occurred in 2013. Even then, that advice was controversial, as it addressed how the governor-general “should” act, rather than simply advising on the powers and conventions that applied and leaving the governor-general to decide how to apply them.

There is currently no clear position in Australia on who should provide legal advice to the governor-general and the constraints upon the type of advice that should be given. This needs to be addressed in the future.

What happens when advice conflicts?

The second question is how the governor-general should deal with conflicting advice, which in 2018 was a real possibility.

For example, the solicitor-general could have taken the same view as the previous acting solicitor-general – that the advice of the outgoing prime minister is binding. The attorney-general, Christian Porter, apparently took the view that it was not binding, and that the governor-general should only consider who held the confidence of the house.

The prime minister is likely to have taken the view that the governor-general was bound to act on his advice not to appoint Dutton as prime minister, or that if the governor-general had a discretion, he should take into account the doubts about legal eligibility and refuse to appoint a person who might be disqualified from parliament.

There is no rule book that tells the governor-general how to deal with conflicting legal and ministerial advice. Ultimately, in this case, it was a reserve power that was in question and the discretion was a matter for the governor-general to exercise.

Confidence and eligibility when appointing a prime minister

Assuming the governor-general accepted the orthodox view that the appointment of a prime minister is a reserve power governed by the convention that the prime minister should hold the confidence of the lower house, what should he have done in this scenario?

The first issue is one of confidence. It is not certain that even if Dutton had been appointed leader of the Liberal Party, he would have held the confidence of the house. There may well have been defections that altered the balance of power.

Read more: The government was defeated on the 'medevac' bill, but that does not mean the end of the government

Hence the governor-general, as occurred in 2013, could have required an assurance to be given by the prospective prime minister that he would immediately face the house to allow it to determine confidence.

The second issue concerns eligibility. The governor-general is obliged to obey the Constitution. If the Constitution plainly prohibits action, such as appointing a prime minister in certain circumstances, the governor-general is obliged to obey it.

But where the legal question is contestable, it is not up to the governor-general to determine it. In this case, the Constitution and the law confer the power on the relevant house, or the High Court acting as the Court of Disputed Returns, to determine disqualification from parliament.

Further, the Constitution allows a person to be a minister, without holding a seat in parliament, for up to three months. So the governor-general could legally have appointed Dutton as prime minister, but might first have required his assurance that he would ensure his eligibility was resolved by a reference to the High Court.

In this way, the governor-general would have protected the Constitution and the rule of law while still complying with the principle of responsible government. Of course, he may have had some difficulty persuading Dutton to give those assurances. But this is precisely why we appoint as governor-general people with the authority and gravitas to ensure that the Constitution is respected and upheld.