In a recent article (The Australian, 15 July), Peter Jennings, a strategist with a long history of government service, commended to President Trump a strategy for defeating Iran.

His article is of interest both for its argument and its realist understanding of strategy. This approach focuses on national interests, power and technology, and measures the value of human beings by how they serve those interests.

It does not attend to ethical arguments except to rebut criticism, as, for example, in defending the bombing of Dresden and Hiroshima.

Seven steps to regime change

Jennings claims that it is in the interests of the United States and the wider world for it to enforce regime change in Iran, the renunciation of its nuclear ambitions and the abandonment of its support for radical groups in the region. He proposes seven necessary steps that President Trump should take.

The first is to order a review of government strategy focusing on ways to achieve its desired military and financial goals. That done, the President should send high-level ministers to Europe to hear their views and persuade them to join the action against the Islamic Revolutionary Guard Corps (IRGC).

He should also send a representative to persuade Saudi Arabia and the Emiratis to support the action. After that groundwork, the President should address the American people to explain that the war must be prolonged until the Iranian regime is removed and to ensure public support for it.

Squeezing Iran’s economy and waters

The United States should then pressure the IRGC by taking control of the Kharg Island oil terminal and enforcing financial sanctions. An international coalition should then escort shipping through the Strait of Hormuz after the US has taken military control of Qeshm Island in the strait.

China should be told that its relationship with the United States depends on its cutting ties with the Iranian regime. Finally, Israel should be asked to participate in military actions to destroy the Iranian leadership.

In outlining this strategy, Jennings acknowledges the importance of international support based on shared interests and the contribution of such good international citizens as Australia.

Where the strategy holds up

Considered only on technical grounds and on an assessment of shared interests, the strategy and its steps are quite straightforward. No doubt, if all the parties involved committed themselves to implementing it, all the steps could be taken.

The obstacles to its success, however, arise when we consider that it will need human beings to carry it through in the face of the differing interests and human frailty of those implementing it, and when we weigh its cost to the human beings and societies affected by it.

In the first place, the plan demands that different human beings with different relationships and interests be prepared to sacrifice some of those interests in order to pursue shared interests. In the conduct of the operation, which will inevitably prove more complex and prolonged than initially foreseen, the various partners’ judgements of what is in their interests will also change.

Interests are important but fragile. Their pursuit depends on immeasurable human qualities.

A plan can be militarily feasible without being politically sustainable, and strategically coherent without being morally defensible. The plan does not sufficiently respect the human dimension of war, nor does it adequately take account of participants’ changing perceptions of their interests.

The question of trust

Chief among these is trust. Before committing themselves to join a concerted action led by other national leaders, people need to trust that those leaders will carry it through steadily, even in the face of unpopularity, and will not serve their individual interests at the expense of their allies.

In concrete terms, this means trusting President Trump to lead the enterprise steadfastly, putting aside his individual interests and desires and enduring harsh criticism along the way.

Some allies might find it difficult to place such trust in any US president, and specifically in President Trump.

It also demands that the leaders of other allied nations, including those in the Middle East, trust the leaders of the other nations in the coalition.

The human cost overlooked

Second, the plan does not take into account the human cost involved in achieving its goal and its effect on relations between individuals and societies.

This systematic failure in the strategic analysis and its potential consequences are most clearly evident in the proposal that Israel provide the force necessary to remove the IRGC.

Israeli action against Hamas in Gaza and Hezbollah in Lebanon was conspicuous for disregarding the human cost to civilians and their living environment. But it failed to destroy Israel’s enemies and has weakened international support for Israel.

To destroy the IRGC would surely be more demanding and its human cost heavier. The allied nations, and Israel itself, would face opprobrium and a shift in interests as the human cost of the adventure became evident.

When interests diverge

Third, because the plan can work on its own terms only when the individual interests of its many participants converge, it is vulnerable at points where they begin to diverge.

As the human costs of the war become evident, the reaction, particularly among people in Muslim nations, will intensify, with the result that it may be in the interests of their leaders to dissociate themselves from the war.

The financial costs of sustaining the war and recreating a stable Iranian government will be heavy.

Will the leaders of allied nations already under pressure from populist movements see it as in their interests to pay these costs?

And how will China and other nations with an interest in weakening the international standing and power of the United States grasp the opportunity offered by the war?

A war within a larger war

Fourth, the object of the plan is to drive the IRGC from power through relatively short but intense military and economic pressure that would disrupt life and institutions.

This might be straightforward if Iran’s rulers conceive of their interests in the same way that strategists do.

It becomes more complex, however, when they are motivated by ideas in which defeat in military action is seen only as an event in a larger war. As has been the case in Israel’s conflicts with Hamas and Hezbollah in Gaza and Lebanon, will the interests driving military action demand a prolonged and self-defeating military presence?

A plan that misses ethics

Jennings’ suggested policy is admirably clear in spelling out the policy President Trump must adopt to serve the interests of the United States and its allies, and how he must involve others in carrying it out.

To this non-expert reader, it appears to recognise the military and technological realities of the challenge posed by Iran and the support required from participants in realising the plan.

The plan, however, fails to respect the human dimension of war, which is spelled out in the ethical basis of the international laws governing the declaration and conduct of war, with their emphasis on protecting non-combatants and their living space.

It also fails to take account of participants’ changing perceptions of their interests.

Lessons from ancient Rome

Given the present state of the conflict, President Trump may see it as in his interests to destroy the governance and economy of Iran. He might profitably, however, attend to the risks of the unmeasured pursuit of self-interest captured in two mordant lines about the conduct of war and government in the Roman Empire.

Tacitus’ remark about one campaign — “They make a desert and call it peace” — warns against unmeasured military action without human restraint.

Augustine’s more general reflection — “If you take away justice, what are kingdoms but great bands of robbers?” — speaks powerfully to the present crisis of governance.

• Andrew Hamilton SJ is the consulting editor of Eureka Street and a writer at Jesuit Social Services.