During the past 50 years the ABC has been criticised by Coalition and Australian Labor Party leaders alike. The unexpected bipartisanship turns on the fact ABC journalists and producers tend to attack both major parties from a left-wing — and increasingly green-left — perspective.

In recent times, Malcolm Turnbull and/or his Communications Minister, Mitch Fifield, have complained to ABC managing director and editor-in-chief Michelle Guthrie on a range of matters.

These include the reporting on tax and innovation by ABC ­economics correspondent Emma Alberici along with statements by ABC political editor Andrew Probyn and ABC 7.30’s chief political correspondent Laura Tingle.

Fifield has accused Probyn and Tingle of repeating “a Labor lie” about the timing of the forthcoming by-elections in Western Australia, South Australia and Tasmania.

When former prime minister Tony Abbott clashed with the ABC concerning Q&A — even to the extent of preventing his ministers from appearing on the program for a couple of weeks — Turnbull, who was communications minister, did not embrace Abbott’s criticism. It is understood his attitude at the time was that most journalists were on the left and it was to be expected that this would be reflected in the public broadcaster. Turnbull appears to have had a change of attitude since moving into the Lodge.

From his early days as prime minister, John Howard called for the ABC to appoint a “right-wing Phillip Adams”. This was another way of saying the ABC was a ­conservative-free zone without a conservative presenter, producer or editor for any of its prominent television, radio or online outlets. Two decades later, nothing has changed.

Labor leaders at the commonwealth level are invariably from the party’s right-wing, or social democratic, faction. Kevin Rudd recently received a grovelling apology from the ABC for its inaccurate reporting in recent times of his government’s home insulation program. And Julia Gillard’s supporters were correct in objecting to the demeaning way in which she was presented in the comedy series At Home with Juliaduring her time in the Lodge.

However, the most serious conflict between the government and the taxpayer-funded public broadcaster took place when, as prime minister in 1991, Bob Hawke effectively accused the ABC of bias in its coverage of the first Gulf war.

Hawke, a member of the ALP’s right-wing faction, clashed with then ABC managing director David Hill, who also happened to be a member of the Labor right. In his semi-official history of the ABC, Whose ABC?, KS Inglis described the resultant controversy as a “public and domestic conflict as troubling as any in the ABC’s history”.

Hawke’s stoush with Hill led to the public broadcaster bringing greater balance to its commentary on the first Gulf war and, on one occasion, providing an ABC critic a right to be heard.

Hawke well understood that he was being attacked on the ABC from the left since many of its journalists and producers opposed Australia’s involvement in the campaign by the UN-approved operation — led by the US — to drive Iraqi leader Saddam Hussein’s forces out of Kuwait.

The problem in 1991 turned on the fact there was an absence of political diversity within the public broadcaster. It’s much the same today. In any organisation without a plurality of views within it, a certain groupthink will form.

This is accentuated by the unwillingness of Guthrie and her predecessors, including Mark Scott, to run the organisation on a daily basis. Instead, power over programming, appointments and promotions is handed to several cliques that prevail over certain programs. 7.30 presenter Leigh Sales denies the ABC is bereft of conservatives on prominent programs, but she has been unable to name one within the organisation.

Writing in Fairfax Media newspapers last week, ABC chairman Justin Milne stepped forward to defend the public broadcaster.

His article was another example of the ABC in denial. He declared that “Australians should not be fooled by the current battle being waged against public broadcasting” and asserted that “fringe political interests, populists and commercial media all have a shared interest in weakening the ABC”.

Well, maybe they do. And maybe they don’t. But the ABC’s immediate problem turns on the decision announced in the 2018 budget that its expected indexed increase in funding across the next three years will be frozen. Fringe political interests, populists and the like do not determine budget decisions.

Also, Milne neglected to address the lack of political diversity in the ABC. On Guthrie’s watch, action has been taken to ensure that the public broadcaster reflects a greater range of views from indigenous, ethnic and religious (primarily Islamic) groups.

However, Guthrie has done nothing to put some political diversity into the organisation. She appears to hold the view that journalism is a left-wing profession and there’s nothing the ABC can do to change this.

Milne ran the familiar ABC line that 80 per cent of Australians regard the public broadcaster as “the most trusted media organisation in the country”. If this is the case, it’s not clear why the Seven and Nine networks’ news services consistently outrate the ABC.

Funding for the ABC has never been an issue in Australian elections and this is unlikely to change in the immediate future. Consequently, it makes no sense for the ABC to be consistently off-side with so many political and social conservatives. It needs bipartisan support.

In the short term, the ABC would be well advised to split the roles of managing director and editor-in-chief and appoint someone to the latter post who is prepared to ensure political diversity at the level of programming and appointments.

Also, the ABC’s editor-in-chief should be equipped to handle criticisms by the likes of Turnbull and Fifield without referring them to middle-level bureaucrats in the first instance. An active editor-in-chief could ensure that the public broadcaster develops a culture of correcting its own errors in real time. It’s not a difficult task.

Gerard Henderson is executive director of The Sydney Institute. His Media Watch Dog blog can be found at theaustralian.com.au.