Progressive Realism: Lord Hermer’s Vision for Law and Security
Dr Brian Brivati, Executive Director, Britain Palestine Project
On 29 May 2025, Lord Richard Hermer KC, the UK Attorney General, delivered the Royal United Services Institute (RUSI) Annual Security Lecture - see official text here with some political elements edited out. His address focused on the role of international law in tackling current geopolitical crises – from Russia’s war in Europe to the escalating conflict in Gaza – underscoring the link between national security and a robust multilateral legal order. Notably, while he cited the Gaza war’s growing brutality as a pressing challenge, he did not offer any legal judgment on that specific situation. Instead, the speech framed a broader doctrine – “Progressive Realism” – as the guiding philosophy reconciling Britain’s strategic interests with its commitment to international law.
Hermer explained that Progressive Realism means “taking the world as it is, not as we wish it to be” in order to “advance progressive ends by realist means”. In practice, this doctrine marries pragmatic national interest with principled support for a rules-based international order. Far from viewing international law as a hindrance, Hermer argued that adhering to legal norms is both “the right thing to do” morally and “the realistic, rational, cool-headed thing to do” strategically. In his view, painstakingly upholding the rules that protect human dignity, fair trade, the environment and defensive alliances is not self-restraint but “pursuing our national interest” – indeed the “only truly realistic choice” for Britain.
Rejecting Idealists and ‘Pseudo-Realists’
The Attorney General sought to defuse what he sees as a false choice in foreign policy between two extreme camps. On one side are “romantic idealists” who treat international law as a moral panacea, insisting Britain should always follow high-minded principle regardless of pragmatic considerations. Hermer characterized this stance as naïvely seeing the world “as [they] want it to be, not as it is,” warning that a foreign policy of unyielding moral absolutism would render Britain a self-righteous but ineffective “pious priest” on the global stage.
At the opposite pole are what he labeled “pseudo-realists,” who argue that today’s volatile world requires abandoning long standing legal and moral commitments. These voices claim the post-1945 international order is unraveling and advocate a return to raw power politics, echoing 19th-century realpolitik and the political philosophy of Carl Schmidt that underpinned the foreign policy of Hitler and the Nazis:
“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.”
Hermer also noted that this view essentially revives Bismarck’s dictum that great questions are settled not by speeches but by “blood and iron”. He condemned such pseudo-realism as a call for a Hobbesian “war of all against all” in place of any rules-based order. Both the idealist and pseudo-realist narratives are “temptingly simple” yet dangerously misguided, he argued, as they misunderstand Britain’s history and the true value of international law. Embracing either extreme would leave the country less safe and less prosperous in a perilous world.
Hermer reminded the audience of Britain’s proud legacy in building the postwar international legal order. After the horrors of the 1930s and World War II, far-sighted leaders – including British statesmen – designed new institutions and laws to prevent a return to global anarchy. The UK played key roles at Yalta, in drafting the United Nations Charter at San Francisco, and in establishing frameworks like Bretton Woods. British jurist Sir Hersch Lauterpacht was instrumental in developing modern international law, and a British Conservative, David Maxwell Fyffe, was a principal architect of the European Convention on Human Rights. This post-1945 order, rooted in law, enabled nations of vastly different systems to cooperate in peace while pursuing their interests. Hermer argued that treating international law as something “foreign” imposed on Britain ignores how much the rules-based order was shaped by British ideals and leadership. The notion of discarding those legal constraints in favor of unfettered state power, he suggested, would betray the lessons of history that Britain itself helped write. Both Conservative and Reform Party spokespeople have called for his resignation for this passage.
International Law, Sovereignty and National Interest
A central theme of the lecture was that obeying international law is fully compatible with – even essential to – national sovereignty and self-interest. Hermer stressed that international law is not an affront to sovereignty but rather founded on it – without a legal order, “sovereignty” would be an empty concept, with borders and rights at the mercy of brute force. When Britain enters a treaty, it does so by choice and in its own interest – there is no “surrender of national sovereignty” in honoring such agreements. Moreover, once committed, Britain cannot cherry-pick which treaty obligations to follow without eroding the entire system’s credibility. Hermer warned that a selective “pick and mix” approach to international rules would lead to the order’s disintegration. Indeed, he noted, the rules-based order “soon breaks down when States claim they can breach international law because it is in their national interests.” That is the very “exceptionalist argument that Russia makes” to justify aggression. Crucially, the UK’s own constitutional tradition has long held that ministers must abide by international law, reflecting a national ethos that if you make a promise, you should keep it. Abandoning that principle, he argued, would be a radical break from British values and would destroy other states’ trust in the UK’s word.
Hermer highlighted how Britain is already reaping tangible benefits from renewing its reputation as a law-abiding international partner. In recent months, the UK has swiftly concluded major agreements – including new trade deals with the European Union, United States and India – and forged closer security cooperation with key allies, precisely because it is once again seen as a “trusted international partner” that honors its commitments. By contrast, he implied that the previous government’s willingness to “play fast and loose” with legal obligations had eroded confidence in Britain, stalling such deals. Upholding the rule of law, therefore, is not an act of altruism but a savvy investment in Britain’s own prosperity and security. As Hermer quipped – channeling a famous Monty Python scene – what has international law ever done for us? It has delivered “peace, security and prosperity,” and can continue to do so if Britain leads in strengthening the system.
Adapting and Reforming the Rules-Based Order
Progressive Realism, as Hermer described it, is not blind to the imperfections of the international system. He acknowledged that international law must evolve to meet new challenges and cannot simply “stand still” or “rest on its laurels”. Not every global problem is covered by current rules, especially amid rapid changes in technology, climate and conflict. Hermer encouraged evidence-based criticism and reform of international norms where necessary, rather than either complacency or wholesale abandonment. International law should neither overextend to dictate every issue nor be used by governments as a scapegoat to avoid hard choices.
As an example of constructive reform, he pointed to the UK’s leadership in refocusing the European human rights system on “subsidiarity.” This principle reaffirms that primary responsibility for protecting rights lies with national authorities, with international courts stepping in only as a last resort. By strengthening this balance, Britain has shown that institutions like the European Court of Human Rights can be updated to respect democratic decision-making while still upholding core principles. Ultimately, tackling emerging issues – from artificial intelligence to climate change to conflicts like Ukraine – will require nations to build coalitions and negotiate new agreements, then “knit” those deals into binding law. Diplomacy and law go hand in hand; as Hermer observed, “You cannot have one without the other.”
Hermer concluded his lecture on a poignant personal note, illustrating what is at stake in upholding international law. He recounted a visit to Ukraine where he toured sites of atrocity: the Babyn Yar Holocaust memorial and the town of Bucha, which had witnessed massacres during Russia’s invasion. At a church in Bucha, he met a priest who had helped bury over two hundred murdered civilians and memorialized hundreds more. When Hermer asked how the clergyman retained faith amid such horror, the priest replied that it “only makes sense if you believe in justice” – a belief that those crimes have shown the world the inhumanity of war and that the perpetrators will be held to account. Importantly, the priest was referring not to divine judgment but to justice under law, including international law, which can restore “stability and sanity” after the “bloody anarchy” that reigns in its absence. This profound encounter reinforced Hermer’s conviction that Britain must not “shrink away from [its] international responsibilities”. Through Progressive Realism, the UK will work to uphold the international rules-based order as a pillar of a safer, more prosperous world for future generations. In the final analysis, Hermer argued, “the true realist sees no other choice.”
The logic of the Attorney General’s speech is clear with respect to Gaza and the West Bank, Israel’s illegal military occupation and full backing for the illegal settlements. The UK government should follow that logic. The BPP Action Plan for UK government action outlines practical immediate steps, starting with recognition of the State of Palestine, that the government could take now to uphold its obligations under international law and align Progressive Realism with equal rights for Palestinians and Israelis.