Network of Christian Peace Organisations

“Exploring and critiquing the moral argument for increased defence spending in the UK and Europe”

A talk by John Heathershaw to the Network of Christian Peace Organisations (also available to download as a PDF). A video of the talk is available on YouTube

21 April 2026

I would like to begin with a poem from the Ukrainian warrior-poet Artur Dron. It may be difficult to hear for some in this audience, but it does need to be heard.

Love digs trenches and lives in them,
gnawing on ice from a hacked-up plastic bottle,
when it suffers thirst at minus twenty.
Love goes out on combat duty,
enters firing positions
with hernias, fever, prostatitis,
with blast concussions, asthma and allergies,
with a high probability
of not making it back,
thinking all the while about
the one most important to them.
Love bears all things, believes all things,
hopes all things, endures all things!

Artur Dron, The 1st Letter to the Corinthians

Perhaps the greatest controversy in the Western Alliance today concerns the ends and means of defence. This is manifest in debates about the level of defence spending and the extent to which the predominant power, the United States, remains committed to European defence. However, underlying these policy debates is a bigger difference between allies over the form and content of “defence”.

Within the just war tradition, there is the explicit prohibition of offensive military action for the expansion of territory or power. Despite the warmongering rhetoric of the US Secretary of Defence Pete Hegseth, in neither faith-based nor secular traditions, is there a credible moral argument for pre-emptive war for defence. Therefore, moral arguments are always made in terms of defence.

They are also made in a context. I’m going to make mine in the UK and wider European context. This is quite different to Artur Dron’s Ukrainian context. However, the two are not entirely distinct and, in our discussion, we may consider what moral responsibility the UK has for Ukrainian defence.

Three moral arguments for increased defence spending

In an opinion piece in The Guardian in February 2026, Air Chief Marshal Sir Richard Knighton is UK chief of the defence staff and Gen Carsten Breuer is German chief of defence presented a moral argument within a wider political argument for increased defence spending. Each of their three main moral claims contains a certain truth but raises further questions.

1. “Rearmament is not warmongering.” This is true as a simple logic statement BUT research demonstrates that arms racing does correlate with the outbreak of war, most famously in the First World War.
2. “It is the responsible action of nations determined to protect their people and preserve peace.” Morally this is correct BUT rearmament is functionally an exercise of the multinational private sector whose responsibilities are to their boards and shareholders.
3. “Strength deters aggression. Weakness invites it.” Again, there is some truth her but, as an axiomatic proposition, it is a misleading claim. Strength exercised in hegemonic alliance structures outside of their sphere of domination (e.g. USA in MENA) leads to armed resistance. Weakness exercised in neutrality and/or non-alignment does not invite aggression.

These claims only make sense as general claims if we assume a world where military power is the predominant power, states are the only significant actors, and every state must be a global actor: act within alliance structures and deploy far beyond its sure.

But do these premises hold and is this actually defence? To address this big question, I will ask and answer three more in the remainder of this talk.

What is defence?

We may identify four features which most commanders and pacifists would accept.

1. Defence is a contested concept – it is not even clear that it is military defence. Compare the idea of defence in the UK’s Strategic Defence Review (the SDR, where defence is global deployment and alliance commitments) with those in ideas of Civil Defence and Unarmed Civilian Protection (where defence is in the protection of public order, human life and dignity). We know from the work of Maija Stephan and Erica Chenoweth that in many conditions, short of invasion by a major power, unarmed civilian defence is more effective in its aims.
2. Defence is not just a matter for the state. Commanders will often speak of a whole-of-society approach. The Prussian theorist of war and defence, Carl von Clausewitz, having observed the Napoleonic citizen-soldier, identified popular passion as on of the three elements of his trinity. But popular and elite interests often differ. Public and private interests
3. The difference between defence and offence is unclear. Is an attack on a missile silo defensive? Or a drone factory? Defence, insofar as it is miliary, always requires lethal weapons. Only civilian defence is distinct from military offence.
4. “Defence” can generate insecurity. It will generate insecurity when it is part of a strategy of global deployment and alliance commitments. This is what we call the security dilemma.

For me, the problem is not defence itself – it is moral to defend the weak. The problem is how “defence” is conceived by the UK government and figures like George Robertson, one of three authors of the SDR, who recently labelled the UK’s failure to commit to very high increases in defence spending as “corrosive complacency”.

Why might strategists doubt the SDR?

Whether or not one is a convinced pacifist, there are many good reasons to oppose the UK’s Strategic Defence Review 2025.

1. Offensive ambitions. The SDR promises that the UK must be ready to “fight and win” a full-scale war. But as my colleague David Blagden assesses, the UK is “looking to perform a great-power foreign policy on a middle-power budget”. That understates the problem. It’s not just the budget. The UK is not a global power anymore, it’s a regional power in resources, status, and influence. For Britain to help keep its region at peace, it cannot play a global military role.
2. Legacies of geopolitics and imperialism. To make sense of this, we need to step back and see these proposals in a broader context. The SDR claims we are in a new era of “state on state conflict” where we move from wars of choice to wars of necessity. But short of an unprovoked invasion, no wars are “necessary”. Afghanistan and Iraq were both presented as necessary by a previous Labour government, but they were not. Moreover, despite the uptick in state on state conflict, the majority of wars and security threats are not state-on-state, as acknowledged by the government’s “integrated review” just four years ago.
3. The funding gap. With a commitment to raise defence spending to 2.5% and the aspiration to move to 3% (by 2034) the SDR promises a “defence dividend” where UK arms companies and areas with bases would benefit. This language inverts the “peace dividend” promised after the cold war, where spending was reduced from an average of 4-5% to 2% per annum. But while spending is now promised to go up, there is no clear plan of how to pay for this, and what social expenditure will be sacrificed or which taxes raised. Moreover, it is well-known that defence spending is one of the most inefficient modes of economic stimulus.
4. The nuclear blackhole. What’s all this being spent on? Much of it is on very expensive high-tech weapons which blurs the boundary between defence and offence. The UK is committed to the renewal of nuclear weapons, has built two big aircraft carriers (but without the navy to fully support them). The SDR says the UK will build “up to 12” advanced submarines and buy up to 12 American F-35A fighter planes (which may carry nukes). The total bill for these will be in the hundreds of billions of pounds – a large proportion of the defence budgets for decades to come.
5. Dependency on the US. In recent years, 86% of British arms imports came from the United States. These big-ticket items are largely about status, not defence. By contrast, Ukrainian defence against Russia is far, far cheaper and largely based on remotely piloted drones built in country (at $400 each). Little of the UK’s super-expensive equipment is necessary for homeland defence.

There are many other critiques one can easily make of the SDR and its argument for re-armament, especially those focused on the extreme inefficiency and corruption in the arms trade. Perhaps we can discuss those later.

What would an alternative defence strategy look like?

Overall, the SDR is fantastical. What would a realistic, hopeful and “Christian” SDR look like? It would not make the classic mistake of confusing the kingdom of heaven and kingdoms of earth by, for example, taking a benign view of Vladimir Putin or assuming that peace itself deters. But it would recognize that earthly kingdoms (including our own) are not forever and therefore placing too much stock in them is folly.

Such an SDR would balance political realism and eschatological hope. The biblical narrative suggests that defence against aggression is a reasonable task in a fallen world but defending an empire, or occupation of the lands of others (as modern Israel does today) is not. This is most clearly presented in the work of Christian prophecy Revelation which reworks Daniel’s warning about the folly of empire. From the perspective of Christian political theology after Christendom, I may offer three suggestions grounded in the biblical narrative of “strategic defence”.

First, the UK should step back from sustaining a global role; in fact, this has not been sustainable for over 100 years. This requires a plan to move the Falklands to international administration and similar moves for other contested territories like the Chagos islands, which has been surrendered to Mauritius and expensively leased back. The UK should abandon a military role in the Indo-Pacific and leave grandstanding there to its erstwhile American ally (which pursues delusions of American-led order or katehon [2 Thessalonians 2:6-7]). This way, money is saved and threats are reduced.

Second, the UK should focus on civil defence. Resources should be focused on cyber, anti-sabotage, and policing territorial waters. Counterespionage, addressing state-linked organized crime, and countering the threat of kleptocracy to the rule of law are also non-military. The SDR’s idea of a new “home defence programme” inevitably recalls Dad’s army but, given the UK is highly unlikely to be invaded, it is a sensible option. After the values of Christendom and empire have rightly die away, Britons are unlikely to fight for keeping imperial territories or being a great power, but they will defend the homeland.

Third, British security should be further Europeanised. We must assume the US is unreliable and unwanted in Europe, abandon the myth of distinct “national interests”, and recognize that we share European interests. The UK has a lot to contribute to European security and to the extent that such security does require expensive and lethal weapons the costs and responsibilities for these should be shared. This makes it less likely they will be used by any one country and, if a clear command structure can be agreed, more likely that they will deter malign powers like Russia.

The British government accepts the final two points in principle. But it is not resourcing homeland security sufficiently because of its delusions of still being a global power. It also seeks greater regional defence cooperation but would dismiss the radical suggestions for Europeanisation and decoupling from the United States. However, if the SDR is to offer hope not fantasy, realism not roleplaying, it needs a strategic rethink. Our ultimate destiny is not ploughshare into swords but one where “nation shall not lift up sword against nation, neither shall they learn war anymore” (Micah 2:4).

Without such hope, what is defence for?

John Heathershaw is Professor of International Relations at the University of Exeter and research associate at the Centre for the Study of Bible and Violence at Bristol Baptist College. He blogs on the Substack “Security After Christendom”. This talk is derived and expanded from the earlier blogpost “Ploughshares into Swords?”