Attorney General's 2025 RUSI Annual Security Lecture
Source: gov.uk (2025-05-28)

On 29 May 2025, the Attorney General Lord Hermer KC delivered the RUSI Annual Security Lecture, reinforcing the government's commitment to international law.

INTRODUCTION

In December of last year, in his Mansion House speech, the Prime Minister recalled the internationalist mindset of the Attlee government of 1945 - that it was only by maintaining our strength abroad that we would be able to succeed at home. The Prime Minister described Attlee’s approach as hard-headed and patriotic – and made plain that the same values would govern our approach to foreign policy.

Building on that theme the following month, in his Locarno Speech, the Foreign Secretary labelled this distinctive approach to foreign and security policy – as Progressive Realism, which he said required:

“Taking the world as it is, not as we wish it to be. Advancing progressive ends by realist means.”

And I would like to take this opportunity today to set out the legal underpinning for Progressive Realism, which I will argue combines both a pragmatic approach to the UK’s national interests with a principled commitment to a rules-based international order.

I am going to start by setting out some of the complexities and challenges of the world that we face, then to address - in order to dismiss - the critique of those I will describe as legal romantic idealists on the one hand, and proponents of what I will call pseudo-realism on the other, before arguing that British leadership to strengthen and reform the international rules-based system is both the right thing to do and the only truly realistic choice.

Before I turn to this, let me first thank Lord Parker for his introduction. Andrew spent his career keeping Britain safe from all manner of threats during a challenging period, before moving on to the Royal Household. So his experience on these security issues has few parallels, and his ability to keep secrets will have been tested in very different ways.

Let me also thank our hosts. It is a real privilege to receive this invitation to deliver the prestigious RUSI Annual Security Lecture. RUSI has held a place of real importance in our public debate for over 200 years. Sitting in government, it is an obvious place to look for expertise, for advice but also for challenge.

No one in this government is under any illusion of the scale of the threats to global security we presently face. The most devastating war in Europe since 1945, the war in Gaza getting ever more bloody and bleak by the day, trade through the Red Sea effectively halted by Houthi attacks, the killing fields of Sudan – we also face profound threats within our own borders from an increasingly assertive axis of hostile states, engaging in espionage, targeting of critical infrastructure and threatening of UK based dissidents; as well as criminal gangs exploiting the most vulnerable by fuelling irregular migration.

As this audience will know better than most, the list of threats goes on. And although some of these threats we have witnessed before, their complexity and unpredictability are unparalleled because they are fuelled synergistically by factors such as how the transformation, of information and disinformation is shared across the globe through social media and increasingly AI – and because we face these threats at this moment in which many are seeking to undermine the multilateral frameworks that have kept us safe since 1945.

The challenges we face are truly enormous and as the Foreign Secretary observed in his Locarno speech the world order had irreversibly changed. The Foreign Secretary said:

“… we have to accept that there is no going back. We must stop the 1990s clouding our vision. The post-Cold War peace is well and truly over. This is a changed strategic environment. … Europe’s future security is on a knife edge.”

Allow me to explain how our policy of Progressive Realism meets this moment. And the role the law, and the international rules-based order plays in our approach. Because our approach is a rejection of the siren song, that can sadly, now be heard in the Palace of Westminster, and in some spectrums of the media, that Britain abandons the constraints of international law in favour of raw power.

This is not a new song.

The claim that international law is fine as far as it goes, but can be put aside when conditions change, is a claim that was made in the early 1930s by ‘realist’ jurists in Germany most notably Carl Schmitt, whose central thesis was in essence the claim that state power is all that counts, not law. Because of the experience of what followed in 1933, far-sighted individuals rebuilt and transformed the institutions of international law, as well as internal constitutional law.

Now part of our pragmatic approach to foreign affairs is to learn from experience – to analyse without preconception or dogma what has been shown to protect British interests in the world and what has not. Schmitt’s so-called realism has for eighty years been refuted by the fact that these institutions, post 45 institutions, have provided the basis until now for Western and other states, wildly varied in nature, to interact with each other under conditions of peace and stability, all the while pursuing their own strategic interests. Raw, wild power, on its own, in so many different calculi, has rarely been picked as a modus operandi because it was not, is not, a realistic way to advance national interests.

Now drawing on historical experience, it is important to stress the role of Britain in the rebuilding of the post war consensus, in the development of international law and multinational institutions – all a rejection of the discredited Schmitt-ian conception of power. Our role then, in Yalta, in San Francisco, in Bretton Woods and beyond helps explain why so many look to us for a leadership role now. There is a temptation among its critics to see international law as something inflicted upon us by others, as something undemocratic and somehow “foreign”. Such assertions frankly smear great the British historic success in providing the international leadership that has established and shaped so much of the rules-based international order. That order was built in the twentieth century on the ideas forged by great British international lawyers, notably Sir Hersch Lauterpacht, the Cambridge Professor of International Law and Britain’s judge on the International Court of Justice. We should not forget that it was a Conservative politician, David Maxwell Fyffe, who was one of the principal drafters of the European Convention on Human Rights.

Let me return to today, where like many public debates in our age of social media, this important, nuanced and complicated discussion about the import of international law is becoming increasingly polarised between what I have described as romantic idealists and pseudo-realists.

Romantic idealists say that international law, conceived as the reign of moral principle, provides a complete answer to any question. To these idealistic champions, British foreign policy is simple. Follow moral principle wherever it takes us. We should always lambast our closest allies regardless of whether or not it is constructive to the politics that we pursue. We should always call out our partners, with different types of governments, regardless of whether the criticism works or whether quiet diplomacy might more effectively produce results. We should always talk to hostile regimes nicely because that will result in them being nicer to us. Such an approach is dangerously naïve – it takes the world as it wants it to be, not as it is. Positioning ourselves as the pious priest, confining ourselves to the comfort of self-righteous declaration, would confine us to irrelevance in global affairs because it focuses myopically on ‘means’ not ‘ends’ – in a manner that ultimately benefits no one.

At the other end of the spectrum, pseudo-realists demand that in these volatile times we must abandon our longstanding commitment to international law and to moral principle.

They say that we are witnessing the unravelling of the post-war international legal order and that the interests of each nation-state must again be superior to any international norms. They are essentially arguing a return to Bismarckian notions of realpolitik. Bismarck said, in 1862:

The great questions of the day will not be decided by speeches and the resolutions of majorities, but by ‘Blut und Eisen’ (blood and iron).

These pseudo-realists advocate for the UK flexing its muscles to make sure it has a seat at the table in the rooms of the powerful where new rules and norms will be forged in the furnace of raw power, rules which may well apply not to all, but only to states in alliances in permanent conflict with other alliances which have chosen to be bound by different rules. There will no longer be a rules-based international order, but rather the war of one against all that Thomas Hobbes famously portrayed as the international state of nature.

[Redacted political content]

What I hope to do is to start to depolarise this debate by setting out the legal underpinning for the principled pragmatism that guides this Government’s foreign and security policy of Progressive Realism. My argument is that we should reject both the pseudo “realpolitik” and the romantic idealists’ view of international law. Their temptingly simple narratives not only misunderstand our history, not only misunderstand international law, it is also reckless and dangerous, and will make us less prosperous, less safe and less secure in a troubled world.

Let me give you four reasons why:

First, we need to be clear that a selective, or ‘pick and mix’ approach to international law by the United Kingdom will lead to its disintegration. The cherry picking advocated by the pseudo-realists is fundamentally at odds with the nature of international law as law. The international rules- order soon breaks down when States claim that they can breach international law because it is in their national interests. That is the present argument advanced by Russia.

The argument [Redacted political content] that the UK can breach its international obligations when it is in the national interest to do so, is a radical departure from the UK’s constitutional tradition, which has long been that ministers are under a duty to comply with international law.

This isn’t Conservatism, this is radicalism, which stands completely at odds with that proud constitutional history in this country. I agree with the views consistently expressed by my, mostly Conservative, predecessors in this role. Dominic Grieve, for example, told the House of Lords Constitution Committee in 2022:

“The duty to observe international law is enshrined in our unwritten constitution because it is Her Majesty’s intention that her servants should observe the binding agreements that her previous servants have entered into—unless, of course, you want to resile from an international treaty.”

And in this country, I believe that the vast majority of people believe that if you make a promise you should keep it – if you enter a contract you should comply with it. Our decency and reliability are our hallmarks as a nation. To similar effect, we also understand that if you sign a contract then you cannot unilaterally choose to comply with some terms but not others – the deal falls through, and no one would trust you enough to secure advantageous terms in the future.

Second, in this dangerous world it is instructive to ask yourself this if the international law framework fails, if our multilateral institutions fall, then Cui Bono? Who benefits? The answer is obvious – it is our enemies who succeed. It is obvious that Russia and other malign state-actors see the undermining of the legal based framework as a core objective. Putin does not simply apply a Schmitt-ian approach to the rule of law within the boundaries of Russia and its proxies, he recognises the huge strategic advantage that would flow in undermining the post 1945 international law framework. It’s why he invokes exceptionalism to justify his crime of aggression, it is why he devotes so many of his resources to undermining democracies and to seeking to fuel divisions within them.

This is why the approach of both romantic idealists and pseudo-realists are not simply wholly naïve but dangerous. There is nothing ‘realistic’ at all about the latter’s views and that is why I label them ‘pseudo-realists’. Their analysis is the precise opposite of realistic – it is deeply unworldly, fit for a university debating chamber perhaps but not the world in which our enemies recognise the strategic benefits of the disintegration of the international rules-based framework and where the stakes for western democracies could not be higher. Let me be crystal clear - I do not for one moment question the good faith let alone patriotism of the pseudo-realists but their arguments if ever adopted would provide succour to Putin.

Third, international law is a key vehicle by which states can both pursue their strategic interests and at the same time give effect to the norms and values that they hold dear. States can amplify and project their hard power, for example, by entering into legally binding treaties creating powerful military alliances with other states, such as NATO, or beneficial intelligence sharing alliances such as the Five Eyes. At the same time, states can also use international law to protect certain values they hold dear; security of our borders, human rights, equality and the rule of law. There is no inherent contradiction between international law and determined pursuit of national strategic objectives. The school of pseudo- realpolitik critique is wilfully blind to the extent to which international law is itself already a framework for principled, pragmatic, pursuit of national interests.

Let me put to bed the notion that international law is somehow an affront to state sovereignty. To the contrary, international law is founded on the idea of state sovereignty. And without international law, there would be no state sovereignty, only the emptiness of that word in a world where hunks could be ripped off borders and every dispute be settled by the force of the strong.

When a state chooses to enter into an international treaty, and it is a choice, that does not involve any surrender of national sovereignty to malevolent international actors or make the state a vassal of international organisations – it is a conscious decision that a state makes in their own interest.

International treaties always recognise that States might disagree about their interpretation. This is why we have dispute mechanisms. This is why states can leave the treaties they have signed and agreed on. But the integrity and force of the system requires that once a party, to an agreement, they abide by its rules — they don’t pick and mix.

Fourth argument is this, our international obligations are not onerous but manifestly in this country’s national interests. This is at the heart of progressive realism. In addition to safeguarding our national interests, as the tectonic plates of the international order shift dramatically, we as a government are seizing the opportunity to provide global leadership, combining hard-headed British pragmatism with our equally strong and hard-earned global reputation for a commitment to international law. We know from experience that we can best achieve our own goals only within a framework of international law that makes the same possible for others.

We have real life experience as a nation in experimenting with pseudo-realism.

[Redacted political content]

By contrast with the inconsistent, flamboyant and on occasion inflammatory rhetoric, this Government is clear that the national interest is served by the restoration of our reputation not simply as a nation that respects its international law obligation but as a leader in the rules-based international order. Our return as a good faith actor has been greeted with warmth across the globe – I have seen it myself in meetings in Kyiv, in discussions with European partners and the halls of the United Nations. What we can feel is a palpable relief that we are stepping up.

Last week, at the press conference marking the historic agreement between the UK and the EU, the Prime Minister said this:

“Britain is back on the world stage … facing out to the world once again in the great tradition of this nation. Building the relationships we choose, with the partners we choose, and closing deals in the national interest.”

The agreement with the EU includes a significant new trade deal with our closest trading partner – it will make a real difference to our economy and the standards of living of our citizens. It is only the recent such trade deal.

There is also the US Economic Prosperity Deal, with the world’s biggest economy and most powerful democracy, and our closest ally.

There is the Free Trade Agreement with India, the world’s largest democracy and our Commonwealth partner which will inject billions of pounds into the economy.

The first ever Economic 2+2 with Japan, a new economic partnership with the world’s fourth largest economy a strong ally of this country in the Pacific.

In is not ‘despite’ of our commitment to international law that trade deals are being signed within months where the previous government failed over years – rather it is ‘because’ we are now once again a trusted partner. Our word is once again our bond – not a phrase that could be uttered in good faith by the pseudo-realists. These successes, secured in international agreements, will be felt in the most concrete of ways of the people of this country – in tens of thousands of new jobs, in the raising of living standards and more money in people’s pockets. This economic benefit is a direct consequence of our return as a trusted partner in the rules-based order.

Beyond trade, we have led efforts to ensure Europe steps up to meet the security challenges flowing from Russia’s illegal invasion of Ukraine. This means supporting Ukrainian efforts to defend itself, readying Europe to step up for any ceasefire or peace and continue to strengthen efforts to deliver a measure of accountability for those responsible for the atrocities involved in Russia’s actions.

More broadly across the European continent, we have concluded a significant new Defence and Security Partnership which substantially strengthens this country’s security. It will upgrade our cooperation on areas ranging from defence industry, mobility of military material and personnel, maritime security and space security. It sets the framework for closer defence industrial collaboration, including potential participation in the EU’s proposed €150bn Security Action for Europe instrument. This on top of the Global Combat Air Programme treaty ratified in December 2024, delivering a next generation combat aircraft for 2035, to keep us ahead of new and evolving threats for decades to come and creating thousands of new jobs, right across this land.

Our good faith adherence to international law brings together other vital interests. We have strengthened partnerships on border security with our nearest neighbours and built their confidence that we can be trusted to be fair and honest in our dealings and bringing to a decisive end what the Prime Minister has described as “gimmicks” which were proving a barrier to effective collaboration. It is no accident that the previous Government who played so fast and loose with our reputation as a leader in international law, were unable to reach any agreements that effectively addressed unregulated migration – yet within months of office the Home Secretary has reached ground breaking deals with France in respect of patrols of their own waterways to stop boats crossing the channel; Germany has agreed to amend its own domestic laws to stop the transport of boats and parts – agreements which are essential components of attempts to clamp down on the criminal enterprise of boat crossings –which would have been inconceivable, inconceivable, whilst the UK was posturing over support for the ECHR and international law more generally.

So, allow me if you will, to channel Reg, the leader of the People’s Front of Judea in Life of Brian and ask rhetorically what has international law ever done for us? Well, the answer is that it has helped give us peace, security and prosperity. And it will continue to do so – this is just the start - together with other initiatives which the Foreign Secretary and others in the Government are working on right now, they will bring tangible benefits to the people of our country. They are the early fruits of the UK’s clear signal to the international community that it can once again be treated as a trusted international partner. A country which will keep its word when it enters into international agreements. A country that stands up for principle and takes a broad perspective on compliance with the law, recognising of course occasional frustrations in the moment but huge benefits in the longer-term.

We are not Progressive Realists because we qualify our realism. We are Progressive Realists because we combine both a commitment to progressive ends with a realistic understanding of how those ends can be achieved in the world as it is. Because a commitment to international law is both the right thing to do and the realistic, rational, cool-headed thing to do. We are Progressive Realists because painstakingly upholding and strengthening the rules that enshrine respect for human dignity, accountability for breaches of international humanitarian law, fair rules permitting free trade, protections of our environment and defence pacts that protect our nation— is not restraining ourselves but pursuing our national interest. And the only truly realistic choice we can make. And it is truly a patriotic one.

We are Progressive Realists because we do not shy away from a belief in the importance of value-based multilateralism as a fundamental force for good in the world - and we recognise the power those ideals both hold and bring us.

The late Kofi Annan once said:

Our enemy now is indifference, the belief that there are many worlds, and that the only one we need to care about is our own.

We will not be indifferent. The promotion of, and compliance with, these progressive values underpinning international law and the multilateral institutions that have grown up to support them over the past 80 years is a source of immense national pride – it is a great British value to say that we want to make the world a better, safer and more prosperous place. There is no contradiction between approaching the world with a hard head but also a warm heart. This is Progressive Realism.

Now, before I conclude, allow me to say something about how international law adapts to the changing challenges we face and the role of nations in shaping it.

As progressive realists we recognise that international law cannot stand still and rest on its laurels. It must be critiqued and where necessary reformed and improved. Nothing I have said here is intended to shield international rules or treaties from evidence-based criticism or proposals to reform. Nor do I argue for one moment that the international law system covers every problem.

As we look to deal with fresh challenges and changes, we must not stagnate in our approach to international rules and customary norms. We must look to apply and adapt existing obligations to address new situations or technological advances. And we must be ready to reform where necessary.

We need to recognise that international law is incomplete. It was not intended, as I said to cover every situation or development. Some areas were deliberately left unregulated or only covered at a high degree of general principle. The legal space has not eliminated the political space. They continue to co-exist, and law, including international law, regulate how they interact.

States agreeing to treaties some time ago did not give an open-ended licence for international rules to be ever more expansively interpreted or for institutions to adopt a position of blindness or indifference to public sentiment in their member states. International rules and institutions should not, without state consent, bend existing rules and obligations to make decisions or trade-offs that are far more effectively and legitimately dealt with through political and diplomatic means. Equally though, states and governments must not use international laws and institutions as a convenient scapegoat to evade taking hard decisions or advocating for reform.

Again, the tincture for any such ills that the system suffers in this way is I suggest a strong dose of balanced British pragmatism and principle. As we have shown time and again as a nation, one from a position of respect and compliance, we have proven that reform is possible and institutions can be reformed. The UK has provided the international leadership for the renewed focus on subsidiarity in the European Convention on Human Rights – reminding both states and the international institutions that the primary responsibility for upholding human rights rests on national authorities, and that the role of the Court is a supervisory one which only need be invoked when the national system for protecting those rights has failed. That focus on subsidiarity, properly understood as a duty on states to implement, revives the importance of political discussion and debate about human rights which is so vital to preserving their democratic legitimacy. International law cannot and must not replace politics.

That’s why Progressive Realism, internationally, is above all the assembling of the necessary coalitions to tackle our current challenges; challenges that appear from AI, climate change and trade, to conflict resolution in places like Ukraine. Because none of these problems can be addressed from the sidelines, where the romantic idealists might relegate us. And all can only be addressed by agreeing and complying with negotiated deals which are then made binding in legal texts - the very power of which the pseudo-realists seek to undermine.

Negotiations, driven by politics and diplomacy, and then knitted together in law, are the answer. You cannot have one without the other, at least not in a way that provides sufficient certainty or sustainability.

Allow me if you will, to end with a personal recollection. In September of last year, I travelled to Ukraine. As part of my visit, I travelled to the outskirts of Kyiv, first to Babyn Yar to pause at the memorial to the thousands of Jews who were murdered there over two bloody days by the Einsatzegruppe in 1941 and then onwards to the town of Bucha, which in the early days of the current conflict marked the furthest point of Russian advance. Many of you will have been there. Some 40 mins or so from central Kyiv, Bucha is a picturesque town with dachas dotted in the forests. I was taken to the gleaming white St Andrew’s Orthodox Church where I was met by the local priest Father Andiry Halavin. He took me first to a plot of grass behind the church where he and others buried over two hundred residents in a mass grave and then next to it a memorial wall with the names of over 500 civilians, murdered in cold blood by the Russian forces – the names on the wall of entire families murdered, of children, of the elderly. I sat afterwards in the church, quietly with Father Andiry and asked him how as a man of faith he made sense of the intense inhumanity that he had witnessed. In some ways it was an unfair question to ask but his response blew me away – it only makes sense, he said, if you believe in justice, that these crimes have shown the world the inhumanity and illogicality of war, and that those who committed the crimes will be held to account. Father Andiry was not referring to divine justice but to justice under law, including under international law and the return to the stability and sanity that it provides – having witnessed the bloody anarchy of its absence.

That experience is a small reflection of why this Government’s approach to the grave challenges of our time is not to shrink away from our international responsibilities but through progressive realism to work to uphold the international rules-based order in our vital national interests and to contribute thereby to making this world a safer and more prosperous place now and for future generations. The true realist sees no other choice.

Thank you very much.