Agriculture Minister Barnaby Joyce described a federal government decision to allow mining on prime agricultural land in his electorate as a sign of a “world gone mad”. Is this criticism of a fellow minister (Greg Hunt) exercising his authority in his portfolio a breach of the principle of collective responsibility, or cabinet solidarity? Yes, it is.

Will anything happen? No, it will not.

Collective responsibility is an axiom of political prudence – if we do not hang together, we will surely hang separately – that has mutated into constitutional convention of how ministers should behave. But it remains convention, a rule – not the law. The key issue is that one person both defines the rules and decides when they will be applied or sanctions exercised. That is the prime minister.

What are the rules?

The rules, as expressed in the 2015 Cabinet Handbook issued by Prime Minister Tony Abbott, are:

A Westminster-style Cabinet is defined by adherence to the principles of collective responsibility and Cabinet solidarity. These principles are the binding devices that ensure the unity of purpose of the Government and underpin the formulation of consistent policy advice. Collective responsibility … requires that whatever the range of private views put by ministers in Cabinet, once decisions are arrived at and announced, they are supported by all ministers… In practice, a decision of the Cabinet is binding on all members of the Government regardless of whether they were present when the decision was taken. Members of the Cabinet must publicly support all Government decisions made in Cabinet, even if they do not agree with them. Cabinet ministers cannot dissociate themselves from, or repudiate, the decisions of their Cabinet colleagues unless they resign from the Cabinet. It is the Prime Minister’s role as Chair of the Cabinet, where necessary, to enforce Cabinet solidarity. In upholding the principles of collective responsibility and Cabinet solidarity, ministers must … not express private views on Government policies nor speak about or otherwise become involved in a ministerial colleague’s portfolio without first consulting that colleague and possibly the Prime Minister.

Joyce’s comments are inconsistent with these clauses – even if it was a ministerial decision, rather than a cabinet one. The minister was operating within his delegated responsibility. Given the chance to say he was speaking as a concerned local member, Joyce insisted he was speaking as the agriculture minister.

But how collective responsibility is defined is, as the handbook notes, up to the prime minister. That was always so. In 1984, Labor minister Stewart West objected to a cabinet decision on the mining and export of uranium. He wanted to resign from cabinet to protect his left-wing credentials, but remain as a minister and oppose the decision in the Labor caucus.

So the prime minister, Bob Hawke, with the drafting assistance of his departmental secretary, redefined collective responsibility in the 1984 Cabinet Handbook:

All Ministers are expected to give their support in public debate to decisions of the Government; non-Cabinet Ministers, however, are not prevented from debating in Caucus decisions in areas apart from their portfolios. Caucus decisions are binding on all Ministers.

The relaxation of collective responsibility for some ministers in caucus was an exercise in political calculation to maintain support. There was, and is, no definitive definition. Only the prime minister can decide when it has been irrevocably breached.

Why nothing will happen in Joyce’s case

In part, nothing will happen possibly because Joyce is deputy leader of the National Party. It is a position that he does not owe to the prime minister. And, traditionally, leaders of the Country Party in coalition had a degree of wriggle room when they had to play to their members: remember John McEwen and Doug Anthony.

In part, it may be because Abbott would prefer to keep a sometimes recalcitrant Joyce in cabinet – and suffer the occasional embarrassment – than have a Joyce martyred for standing up for his country constituency on the backbench as a running critic. It is a calculation based on political reality, rather than constitutional rectitude.

There are occasions when collective responsibility is not applicable but is still evoked. It may be Liberal policy that there is no conscience vote on same-sex marriage, but party policy can be debated and discarded – as a number of election commitments have been.

Unless it becomes a cabinet decision, pushed through against the stated opinions of senior ministers, it is not yet a government decision. So Eric Abetz’s suggestion that ministers who do not like the policy should resign is stretching the meaning.

Abbott’s ban on frontbenchers appearing on the ABC’s Q&A program is not an application of collective responsibility either. No-one has suggested that Joyce or Communications Minister Malcolm Turnbull were going to challenge government policy on the program. On the contrary, they would have been there to advocate it enthusiastically.

The ban is just part of government strategy to mute criticism. Political strategy is not cabinet policy to which collective responsibility refers.

Nevertheless, in one sense, all these examples come under the same broad rubric: what does Abbott want to do to manage his government in a way that best achieves his purposes?

Interpreting collective responsibility, keeping items off the agenda, controlling access to the media all fall under that title. They always did. The interpretation and application of collective responsibility always was less a constitutional requirement than a captain’s call.