It might therefore appear ironic that his recent address to the Institute of Public Administration Australia should include an eloquent defence of traditional Westminster principles of an apolitical career public service working under democratically elected ministers.

"Westminster principles", however, is a term of fluid meaning. If Pezzullo chooses to play down the importance of anonymity he does, at least, emphasise the core conventions underpinning the Australian Public Service. Moreover, he locates them historically in the context of our British-derived system of government based on the responsibility of ministers to Parliament and a merit-based permanent bureaucracy. None of this should be news to the average Informant reader, but it always bears repeating, particularly by senior members of the APS. Pezzullo believes, rightly, that worthwhile traditions need to nurture their defining histories, a view that has not always been evident in central agencies such as the Public Service Commission and the Department of the Prime Minister and Cabinet.

Cynics may see Pezzullo's manifesto as directed towards the leadership of the Labor Party, burnishing his credentials as a career public servant capable of loyally serving either side of politics. Whatever his motives, however, his arguments are welcome and worth taking seriously.

His main emphasis is on the relationship between public servants and politicians, where he stresses the need for public servants to appreciate the political context in which they operate and to respect the right of elected ministers to determine policy directions. In making these points, he returns to sources that were well known to earlier generations of commentators on the APS. He quotes the famous remark of Paul Hasluck, long-standing minister in the Coalition governments of the 1950s and 1960s and later governor-general, in his Garran oration of 1968, that "the public service cannot avoid politics any more than fish can avoid the water in which they swim". Pezzullo also firmly rejects the view that public servants should set themselves up as "guardians of the public interest", wording that recalls the vigorous academic debates over managerialism in the late 1980s. At that time, critics of the new emphasis on managing for objectives saw it as undermining the public service's traditional role as defender of constitutional values and concern for the common good. Reformers, on the other hand, rejected any implication that public servants rather than elected politicians should decide what was in the public's interest or that public servants should see themselves as guardians of a greater good. By adopting this language, Pezzullo might appear to side with the reformers against the traditionalists.

In spelling out the details of the relationship, however, he takes a balanced approach that gives due weight to the unique role of public servants as partners with ministers in the executive. While always acknowledging the right of ministers to decide major issues of policy, only apolitical career public servants can give ministers the benefits of accumulated policy experience and knowledge. They have a role as custodians of administrative continuity as well as being repositories of strategic policy capability and service delivery competency. In this way, they are crucial in helping ministers formulate a reasonable view of the public interest. Public servants are expected to act "in the public interest" in matters of process, including respect for impartiality, honesty, legality, avoidance of conflict of interest and so on. What they should not do, however, is usurp the politicians' right to determine the public interest.

The phrase "guardians of the public interest" has outlived its usefulness. It indicates an extreme and untenable view of the public service's role in relation to ministers, a straw-man caricature that can be easily discredited. In practice, in a constitutional system of government with checks and balances, no single person or institution is in charge. Ministers certainly approve the policy framework within which public servants operate. But public servants independently protect important constitutional processes under the law, an obligation that can lead them into conflict with their political masters. Moreover, long-term responsibility for the public service as an institution, "stewardship" as it is now called (a term rarely heard a generation ago), has largely shifted from ministers to senior public servants.

Some academic writers on public administration, following Harvard scholar Professor Mark Moore, now prefer to use the concept of "public value" rather than "the public interest" to describe the basic principle motivating public servants. Though etymologically equivalent to "the public interest", "public value" is understood somewhat differently to describe the benefits that public managers seek to achieve for their communities. In this pursuit, managers are required to deal with several constraints, including the need to satisfy the authorising political environment and relevant stakeholders and the need for adequate financial and administrative resources.

The key contrast with the Westminster paradigm is that working towards the elected government's objectives is no longer front and centre but only one factor among many. The model works well in the United States, where the separation of executive and legislative powers means government agencies serve two political masters with divergent priorities. In Australia and elsewhere, it also fits situations where political direction is minimal and managers have considerable discretion in setting strategic directions. This is the case for most local government managers and many managers at the state level. In the federal government, however, particularly for departments under direct ministerial control, the mandate of ministers, reinforced by intense media and parliamentary scrutiny, tends to dominate. Managers still have discretion but it is severely constrained by the overriding imperative to serve the minister and government of the day. In this context, it makes sense to describe public servants as pursuing the public interest determined by ministers.

Pezzullo's emphasis on political direction has no doubt been reinforced by his experience with immigration and border protection. His portfolio has been required to implement highly controversial policies, particularly on asylum seekers. Many of his subordinates have had misgivings about being required to act in breach of Australia's international obligations. They have needed to be reminded that, as loyal public servants, their duty is to implement government policy, however repugnant they may find it. Pezzullo's argument in this lecture, that those who are very strongly opposed should resign and stand for office themselves, is probably one he has advanced many times internally with colleagues.

Immigration policy classically illustrates the Westminster conventions at work, with ministers taking clear public responsibility and public servants in the role of dutiful administrators. But the system requires both partners, ministers as well as public servants, to make their own contribution, a point Pezzullo is too discreet to insist on. Ministers should not expect loyalty from their departments unless they are prepared to front up and take their full share of responsibility. Too often, ministers are happy to devolve responsibility and accountability on to public servants, especially when things go wrong. The infamous home insulation ("pink batts") policy, the most thoroughly investigated recent example of policy failure, is a case in point. The overriding cause of failure was relentless political pressure from ministers determined to spend quickly without due attention to risk. In the aftermath, however, public servants, especially the hapless staff of the Environment Department, were left to bear the brunt of public criticism.

Centrelink's robo-debt fiasco was another example where the general direction of policy was set by ministers seeking to reduce costs and punish welfare recipients, but bureaucrats were held publicly accountable.

The most recent instance of ministers abdicating responsibility concerns the Agriculture Department. As part of his response to media reports of shocking conditions on ships transporting live sheep, the minister, David Littleproud, commissioned an independent report on the department's regulatory capability and culture in relation to live-animal exports. The report, by experienced consultant Philip Moss, was published in September and provides a devastating critique of where the department failed in its task of regulating the live-sheep trade. Too much trust was placed in the industry's capacity to self-regulate. The resources devoted to overseeing animal welfare were insufficient and inefficiently dispersed throughout the organisation. The department's culture gave excessive priority to promoting trade at the expense of animal welfare, and penalised officials who stood up for animal rights.

None of this, however, happened in a political vacuum. The department's worst derelictions occurred after the National Party had returned to power in 2013 and its leader, Barnaby Joyce, took the agriculture portfolio. The party was (and still is) opposed to any restrictions on live-animal exports. Joyce approved the dismantling of the department's animal welfare branch and welfare strategy as part of the government's deregulation strategy. Departmental officials would have been expected to respond to the new government's change of emphasis.

Moss provides evidence for sheeting home a major share of the responsibility to Joyce and his colleagues but is formally constrained from explicitly joining the dots. The new minister, Littleproud, for his own political reasons, is reluctant to have the finger pointed at his predecessor or his party. In the meantime, the department is exposed to full-on attack without any protective ministerial cover.

If ministers want senior public servants like Pezzullo to advocate loyal partnership with the government of the day, they need to keep their side of the bargain and take their full share of responsibility for actions taken in their name.

Richard Mulgan is an emeritus professor at the ANU's Crawford school of public policy. richard.mulgan@anu.edu.au