Hard Law in Times of Liquid Modernity: Treaty Law and Practice in the 21st Century

by Stephan Kinsella on December 2, 2025

Fascinating recent lecture by Santiago Villalpando, Legal Advisor and Director of UNESCO. This is the Eli Lauterpacht Lecture 2025 for the Lauterpacht Centre for International Law at Cambridge University (where my former teacher Rosalyn Higgins is Honorary Fellow): ¹ “Hard Law in Times of Liquid Modernity: Treaty Law and Practice in the 21st Century.” (apple podcasts)

The lecture is inspired, in part, by Zygmunt Bauman, Liquid Modernity (Polity 2000):

In this new book, Bauman examines how we have moved away from a ‘heavy’ and ‘solid’, hardware-focused modernity to a ‘light’ and ‘liquid’, software-based modernity. This passage, he argues, has brought profound change to all aspects of the human condition. The new remoteness and un-reachability of global systemic structure coupled with the unstructured and under-defined, fluid state of the immediate setting of life-politics and human togetherness, call for the rethinking of the concepts and cognitive frames used to narrate human individual experience and their joint history.

This book is dedicated to this task. Bauman selects five of the basic concepts which have served to make sense of shared human life – emancipation, individuality, time/space, work and community – and traces their successive incarnations and changes of meaning.

Liquid Modernity concludes the analysis undertaken in Bauman’s two previous books Globalization: The Human Consequences and In Search of Politics. Together these volumes form a brilliant analysis of the changing conditions of social and political life by one of the most original thinkers writing today.

Podcast description:

Lecture summary: Is international law facing a decline of treaties?

In recent years, several authoritative voices have pointed out certain developments which seem to indicate that States are shifting away from treaty law-making for the governance of their international relations.

Taking as a starting point the sociological concept of “liquid modernity” introduced by Zygmunt Bauman, this lecture will explore how treaties, archetypes of solid and stable law-making, have reacted to an unstable global community where norms seem to be eroding and long-term commitments appear to be challenged.

As the lecture will show, there is no doubt that the law and practice of treaties have evolved to adapt to a shifting international environment, but the news about the death of treaties is greatly exaggerated.

The Eli Lauterpacht Lecture was established after Sir Eli’s death in 2017 to celebrate his life and work. This lecture takes place on a Friday at the Centre at the start of the Michaelmas Term in any academic year.

These lectures are kindly supported by Dr and Mrs Ivan Berkowitz who are Principal Benefactors of the Centre.

https://www.law.cam.ac.uk/people/academic/ja-klabbers/90625

Shownotes (Grok)

Topical Summary of the Eli Lauterpacht Lecture 2025

“Hard Law in Times of Liquid Modernity: Treaty Law and Practice in the 21st Century”

Speaker: Santiago Villalpando

Core Thesis

International law is not witnessing the death or decline of treaties. Rather, treaties are undergoing a profound adaptation to the conditions of “liquid modernity” (Zygmunt Bauman’s sociological concept of a world of flux, instability, eroding norms, and weakened long-term commitments). Far from disappearing, treaties remain central but have been forced to evolve in form, function, and practice to survive in a faster, more fragmented, and more competitive normative environment.

Point of Departure: Liquid Modernity Meets Treaty Law

Bauman’s “liquid modernity” describes a shift from solid, durable social structures to fluid, transient, constantly changing ones (lifetime marriages → diverse family forms; lifelong jobs → gig economy; physical libraries → cloud streaming, etc.).
This liquidity is accompanied by an erosion of stable norms and a reluctance toward long-term commitments.
Treaties, as the quintessential “hard,” binding, stable, written form of international law, appear at first glance to be the prime victims of this trend.

Perceived Evidence of Treaty Decline (and Why It Is Misleading)

Proliferation of informal instruments (MOUs, joint statements, political declarations)
→ Often overstated. Many “informal” instruments are still treaties under the Vienna Convention definition (e.g., ICJ 2011 Kenya-Somalia MOU case).
→ Treaty registration statistics show the opposite of decline: from ~5,000 treaties per decade (1945–1970) to 10,000–12,000 per decade today. Everyday cooperation (taxation, aviation, investment, diplomas) remains overwhelmingly treaty-based.
Shift from binding codification treaties to soft-law outputs at the UN
→ True for the International Law Commission/General Assembly (e.g., Articles on State Responsibility left in limbo), but limited to the codification sphere.
→ Recent years have seen major new multilateral treaties (Paris Agreement, Nuclear Weapons Ban, BBNJ Agreement, Pandemic Agreement, ongoing plastics negotiations).

Real Challenges Facing Treaties

Acceleration of customary international law (“high-speed custom”)
- Custom now forms in years rather than decades or centuries (disarmament, IHL, environment, cyber).
- Driven by intensified state practice and, above all, by the explosion of international courts and tribunals that cite and solidify norms rapidly (Luigi Condorelli’s term: “haute-vitesse custom”).
Explosion of soft law (declarations, guidelines, frameworks, codes of conduct)
- Faster to negotiate, no ratification needed, politically easier.
The lethal combination: soft law + high-speed custom
- Non-binding texts (UDHR, ILC draft articles) are repeatedly cited by courts and tribunals → crystallisation of binding customary law without any treaty ever being concluded.
- Classic example: the plea of necessity in investment law built almost entirely by dialogue between ILC drafts and arbitral awards.

Central Metaphor: The “Netflix Dilemma”

Treaties were once the revolutionary, disruptive technology of law-making (fast + written + binding), marginalising slow customary law in the 20th century.

Soft law and high-speed custom are now the Hulu, Disney+, and Amazon Prime of norm-creation, challenging treaties’ former monopoly and creating the impression of decline.

Yet, just as Netflix did not die but adapted, treaties are responding in two ways:

How Treaties Are Adapting

A. Focusing on their irreducible competitive advantages (things only treaties can do well)

Create international organisations
Establish compulsory dispute-settlement mechanisms
Secure firm financial commitments
Trigger domestic implementing legislation (e.g., international crimes)
Give smaller and less powerful states real influence in multilateral negotiations (Paris Agreement 1.5 °C target driven by small island states)

B. Becoming themselves more “liquid” – profound flexibilisation of treaty law and practice

Entry into force by signature or exchange of notes instead of ratification
Consensus “package-deal” diplomacy instead of article-by-article voting
Fluid titles (agreement, arrangement, MOU, joint declaration)
Deliberately vague, open-textured, “never-ending” provisions (Paris Agreement adaptation article)
Framework convention + protocol + annex + schedule architecture with simplified amendment procedures
Individually tailored commitments (opt-ins, opt-outs, reservations)
Evolutive interpretation via subsequent agreement and practice
Frequent formal amendments (Rome Statute amended seven times in its first 20 years)
Permanent institutional machinery (COPs, MOPs, scientific and compliance bodies) that turn treaties into ongoing negotiation platforms rather than final settlements

Conclusion and Broader Significance

The “death of treaties” narrative is greatly exaggerated. Treaties have not declined; they have metamorphosed. They retain unique strengths and have deliberately incorporated liquidity into their DNA to remain relevant.

In an anxious era of eroding global institutions and contested values, this resilience matters profoundly. History shows that after major ruptures (Westphalia, Vienna Congress, UN Charter), the international community has always turned to treaties to rebuild order. Emphasising that treaties remain adaptable, robust tools offers a message of hope: even in liquid modernity, international law still possesses the instruments needed to reconstruct stability when the world most needs it.

Overview of Liquid Modernity by Zygmunt Bauman (Grok)

In Liquid Modernity (2000), Zygmunt Bauman argues that contemporary society has shifted from “solid” modernity—marked by rigid institutions, stable hierarchies, and durable social bonds—to “liquid” modernity, where everything is fluid, transient, and subject to constant change. Solid modernity, tied to industrial capitalism and nation-states, emphasized heavy hardware like factories and bureaucracies that fixed space and neutralized time, providing predictability at the cost of individual freedom. Liquid modernity, driven by globalization, deregulation, and consumer culture, prioritizes software, mobility, and instantaneity, dissolving fixed structures and making time the dominant force—fluids flow, spill, and adapt without holding shape. This transition, Bauman posits, intensifies modernity’s “melting” tendencies, but now targets interpersonal bonds, turning emancipation from collective liberation into an individualized struggle against systemic insecurity. As he quotes Paul Valéry in the foreword, the core dilemma is whether humans can master their own fluid creations, amid a world craving novelty yet plagued by boredom and incoherence.

Bauman structures his analysis around five key themes—emancipation, individuality, time/space, work, and community—showing how liquidity erodes solid anchors, fostering anxiety, isolation, and “zombie categories” (outdated concepts like class that persist without vitality). Power becomes elusive and extraterritorial, evading accountability while demanding perpetual self-reinvention; freedom morphs into compulsion, as individuals “shop” for identities in a market of ephemeral choices. This is not postmodern rupture but modernity’s radicalization: the quest for progress now undermines collective agency, leaving personal troubles disconnected from public issues. Bauman’s metaphorical style—liquidity as liberating yet disorienting—highlights how neoliberalism frames this as empowerment, while critical theory struggles in a fragmented society.

The book has been hailed for its prescient critique of late capitalism, influencing discussions on precarity and digital nomadism. However, critics note its Eurocentrism and pessimism, lacking solutions or attention to resistance. A 2004 review in Acta Sociologica by Peter Abrahamson calls it a “brilliant diagnosis” but faults its North American bias as a stand-in for global trends . On Goodreads, readers average 4.0/5, praising its relevance to gig economy alienation but critiquing vague empirics . A Reddit thread describes Bauman’s “waffly” style as mirroring liquidity, aiding immersion but frustrating clarity .

Foreword: On Being Light and Liquid

Bauman introduces “fluidity” as a metaphor for the current modern phase, drawing from physics: liquids and gases flow, change shape under stress, and prioritize time over space, unlike solids that resist and “cancel” time. Fluids travel easily—spilling, leaking, dissolving obstacles—associating with “lightness” and mobility, where lighter loads enable faster movement. Modernity has always involved “liquefaction,” melting premodern solids, but now enters a novel liquid stage where nothing holds form long, demanding dated “snapshots” of reality. This captures a society of interruption, incoherence, and constant stimuli, where humans struggle to master their creations, as Valéry questions.

The foreword sets the book’s tone, linking liquidity to broader themes like eroded bonds and perpetual change, without fixed space or time. It critiques how solids (stable structures) yield to fluids’ inconstancy, foreshadowing analyses of individuality and community dissolution.

Commentary often highlights this metaphor’s elegance; a Project MUSE review notes its use to probe transformations in five domains . A Unisalento PDF review ties it to rejecting unequal politics .

Chapter 1: Emancipation

Bauman explores emancipation’s “mixed blessings,” from collective freedom in solid modernity to individualized burdens in liquid times. Freedom once meant liberation from oppression via critique and communal action, but now reframes systemic issues as personal failures, widening the gap between de jure rights and de facto autonomy. Critique’s fortunes change: once bridging private troubles and public issues, it now faces a fragmented society of individuals, where critical theory (e.g., Adorno, Habermas) mourns lost collective targets. The individual combats the citizen, as negative freedom dominates without enabling positive agency, fostering anxiety amid eroded norms (anomie).

Revisiting critical theory, Bauman argues it must reconnect individual and common goods, critiquing life-politics that privatizes emancipation. Panopticon-style control shifts to light modernity’s self-surveillance, where top-down duties cede to bottom-up struggles.

A SoBrief summary emphasizes this shift’s ambiguities . Reddit users link it to failed movements like Occupy, blaming liquidity .

Chapter 2: Individuality

Contrasting heavy (production-focused) and light (consumption-driven) capitalism, Bauman shows individuality as fate yet unattainable capacity. “Have car, can travel” symbolizes illusory mobility; compulsion becomes addiction, as bodies are commodified for market appeal via fitness and shopping rituals that exorcise voids. “Stop telling me; show me” reflects performative selfhood, where shopping divides winners from losers, blending into daily life—shopping at work, home, dreams.

Individuality shifts from solid work/community forging to perpetual performance, with “divided, we shop” highlighting inequality’s reinforcement. Identity is fluid, commodified, echoing liquidity’s inconstancy.

Amazon’s blurb notes five concepts’ analysis . Goodreads critiques elitism but praises gig economy prescience .

Chapter 3: Time/Space

Strangers meet in liquid spaces: “emnie” (predictable), “phagic” (consuming), “non-places” (transient like malls), and “empty” ones fostering isolation. “Don’t talk to strangers” norms arise amid compressed space and stretched time. Modernity’s time history: heavy era conquered space via hardware; light era’s software enables instant living, seductive lightness masking rootlessness.

Time dominates, with instantaneity nullifying space’s value; humans experience disorientation in hyper-mobile worlds.

Polity’s site echoes heavy-to-light shift . Wiley’s similar .

Chapter 4: Work

Progress once trusted history’s arc via labor’s rise; now, work falls from solid “marriage” (lifelong) to liquid “cohabitation” (precarious). Procrastination history shows delayed gratification’s erosion; fluid bonds perpetuate non-confidence, with short-term gigs breeding insecurity.

Work ethic fades; tinkering replaces grand designs, as heavy capitalism’s engagement yields to light’s disengagement.

Sage review views it as mobility-emphasizing consumer society .

Chapter 5: Community

“Nationalism, mark 2” seeks unity via similarity, not difference; security costs freedom, post-nation-state. Filling voids with “cloakroom communities”—ephemeral, defensive against outsiders.

Communitarianism’s gospel promises belonging but demands purity, projecting fears onto “them.”

Project MUSE notes community domain .

Afterthought: On Writing; On Writing Sociology

Sociology parallels poetry/history in uncovering realities, stepping beyond vanishing presents. Creation breaks rules; impurity and unfulfillment mark communication.

Sociologists interpret worlds, disclosing risks amid pressures for conformity.

Unisalento PDF ties to broader modernity .

Transcript (Grok/Youtube)

Cleaned and Structured Transcript

Eli Lauterpacht Lecture 2025

“Hard Law in Times of Liquid Modernity: Treaty Law and Practice in the 21st Century”

Speaker: Santiago Villalpando (Legal Advisor and Director, UNESCO)

Delivered at the Lauterpacht Centre for International Law, University of Cambridge

(Original recording: https://www.youtube.com/watch?v=z2EbOtRC7wI)

[0:00] Introduction by the Host

Jan Klabbers

Good afternoon, ladies and gentlemen. My name is Jan Klabbers. I’ll be your host for the next hour.

I have the pleasure of introducing the speaker of our Eli Lauterpacht Lecture 2025, Santiago Villalpando. I’ll say a word about Santiago in a moment, but first a word of gratitude to Ivan and Francesca Berkowitz for sponsoring the event.

Santiago – I can call him Santiago – is a bit of a rare beast in the sense that he is one of those practitioners in international law who is also very comfortable moving in academic circles. No matter how the coin drops, which probably determined where he ended up, he was the Chief of the Treaty Section at the Office of Legal Affairs of the United Nations – still one of the best seminars I ever participated in, chaired by him, and it was not due to our presentations but to the quality of the chairing.

Before that he had spells at the International Court of Justice, at the International Criminal Tribunal for the Former Yugoslavia, at the UN Dispute Tribunal. He is currently Legal Advisor – very much a hardship posting in a very troubled part of Paris.

Santiago has been a member of the Institut de Droit international since 2021 or so – it says online, so it must be true. He also has a PhD from the Graduate Institute in Geneva, which is a place close to my heart, and a Master’s degree from LUISS in Rome, which is also close to my heart. It’s amazing how much overlap there is. He has been with the Leiden Journal for about a decade, giving academic credentials street credibility. Author and editor of several books, including one I had a chapter in – the Oxford Handbook of UN Treaties – and he, as editor, was assigned to me. We had a lot of correspondence going back and forth, and I may have been more stubborn than I should have. I belatedly apologise.

The topic of the lecture – “Hard Law in Times of Liquid Modernity: Treaty Law and Practice in the 21st Century” – taps into a lot of my sensibilities; the title alone. So, Santiago, I can’t wait. The floor is yours.

[2:54] Opening Remarks

Santiago Villalpando

Thank you very much, and it is a pleasure – and let me say how much of an honour it is to be invited to give this lecture today. It is my first time in Cambridge, which I consider to be an enormous flaw in my career not to have been here earlier, but I’m so happy to be with you today and so happy to see so many friends new and old in this room. Again, thank you very much. Thank you for that introduction.

[3:39] Title and Connection to Eli Lauterpacht

Santiago Villalpando

I’m going to talk today about what I entitled “Hard Law in Times of Liquid Modernity: Treaty Law and Practice in the 21st Century”. I’d like to believe that this is a topic that Eli Lauterpacht would have actually liked a lot, because he is often credited as being one of the promoters of a review of multilateral treaty law-making that was launched by the General Assembly in the Sixth Committee in the 1970s. When he was taking the floor in 1975 on behalf of Australia at the Sixth Committee of the General Assembly to defend that idea, he said – and I quote – “International legislation by treaty-making is an art, a complex and flexible technique which has changed as society has changed.”

This is the topic of today’s lecture: how treaty-making has changed as society has changed.

[4:54] The Gift that Sparked the Reflection – Zygmunt Bauman’s Liquid Modernity

Santiago Villalpando

A few years ago, my wife’s best friend was coming to The Hague for a visit at our home. She was coming from Argentina; she knew my wife pretty well and knew very well what to bring for her. She didn’t know me that much and had no clue what I would like. So she was wondering what I would like as a gift, and she bought me, blindfolded, a book by a Polish-British sociologist named Zygmunt Bauman entitled Liquid Modernity. I remember that this puzzled me and even worried me a little bit at the time. But it turned out that she knew me much better than both of us had thought, since that book triggered for me a reflection that has accompanied me for years about international law and which constitutes the basis of today’s lecture.

Describing in a few words – which I should say is not the way Bauman describes it – the concept of liquid modernity lies in the idea that our society has evolved from a traditional “solid” state characterised by predictable and enduring social structures to a “liquid” one in which social roles and institutions are fluctuating and unstable.

There are numerous illustrations of this around us:

in our families, which used to be built around a lifetime marriage but come today in very different forms;
in our professions, where we used to get a job early in life and stay there until retirement, whereas now we are changing in a more dynamic, more unstable relationship with our lives;
in communication, which used to rely on very solid books kept in very solid libraries, while now we are storing information in the cloud and consume it through streaming and surfing the web – all very liquid images;
in our relationships, which used to be built around stable social circles and now rely on ethereal online networks;
in our political activity, which used to rely on very stable political parties and now is very much shifting to social movements that are united only for one election or one specific topic;
and in the scenery of our lives, where we now move and travel and migrate.

What interested me at the time – and forms the basis of this lecture – is that Bauman also associates this concept of liquid modernity with the erosion of norms and the decline of long-term commitments, which at last leads me to international law and to the subject matter of treaties.

[8:02] Treaties as the Archetype of “Solid” Law

Santiago Villalpando

Treaties appear, after all, to be the epitome of that world that Bauman claims to have been transformed. They are the archetype of what we call “hard law”, which represent all that is solid and stable about our international order. One may then wonder whether, in a world of liquid modernity and erosion of rules, treaties are not themselves being eroded. And many in our discipline seem to have argued so.

A few years ago, a former Director of the Lauterpacht Centre, James Crawford, wondered whether the world is suffering from “treaty fatigue”. A decade ago, the American Journal of International Law organised an online agora on the topic “The End of Treaties?”. And we do see in our daily life several well-known instances of withdrawals from major multilateral treaties – the United States withdrawing from the Paris Agreement, or indeed Brexit – and we also see difficulties in the negotiation of new multilateral treaties such as the treaty on plastic pollution.

So my lecture today is aimed at addressing this question: Are we facing in international law a phenomenon of liquid modernity which is leading to a decline of treaties as a law-making technique?

[9:40] Structure of the Lecture

Santiago Villalpando

To answer this question I will:

describe the symptoms that are often invoked as evidence of a decline of treaties but show that they are not really conclusive of such a decline;
examine what I see as the main challenges to treaties as a law-making technique; and
offer my take about what is happening – namely not a decline, but certainly a reframing of the role of treaties in contemporary international law.

[10:36] Part 1 – Alleged Symptoms of Decline (and Why They Are Not Conclusive)

Santiago Villalpando

A. The rise of informal/flexible arrangements

Those who claim there is a decline point first to the fact that states seem to be favouring more flexible kinds of arrangements. This is undoubtedly true. Where 19th-century international law seemed to rely almost exclusively on a very stable set of formal treaties adopted through a cumbersome procedure of signature and ratification, today’s international affairs are governed by a myriad of flexible arrangements – memoranda of understanding, joint statements, minutes, letters of intent, constitutional arrangements, exchanges of notes – that states seem to be favouring over the traditional structures of treaties.

I do not believe, however, that the rise in such informal arrangements necessarily confirms that treaties are declining. First, the phenomenon is often overstated. On many occasions these arrangements, while certainly more informal than the old-fashioned treaties of the 19th century, remain treaties under international law. Take the example of memoranda of understanding. While it is sometimes thought that MOUs are necessarily non-binding and therefore outside “real” treaties, the fact is that in certain circumstances MOUs may be binding. You don’t need to take my word for it – just read the definition of a treaty in the Vienna Convention on the Law of Treaties, or read a recent judgment by the International Court of Justice where it found that an MOU between Kenya and Somalia constituted a binding agreement (therefore a treaty) on maritime delimitation in the Indian Ocean.

But most of all, this claim seems to underestimate the breadth of international relations. They may be invisible to the untrained eye, but there is an outstanding number of treaties that continue to govern everyday relations between states. In a past position I used to head the UN office in charge of the publication of the United Nations Treaty Series. When you look at the UNTS, it becomes evident that the conclusion of treaties is far from slowing down. The average number of treaties registered with the United Nations in the 1945-1970 period was around 5,000 per decade. More recently it is in the range of 10,000–12,000 per decade – more than 1,000 treaties per year. Areas that continue to rely very heavily on treaties include financial cooperation, double taxation, air traffic, diplomatic privileges and immunities, visa exemptions, recognition of university diplomas, and of course investment protection (remember what investment lawyers keep telling us: there are more than 3,000 bilateral investment treaties).

B. Shift away from the conventional form in codification

A second phenomenon often invoked is that codification of international law has been shifting away from the conventional form. This is also true. In its early decades the United Nations seemed set on codification through major conventions – the Vienna Convention on Diplomatic Relations, the Vienna Convention on Consular Relations, the Vienna Convention on the Law of Treaties, etc. Lately the UN has favoured more flexible non-binding instruments – guidelines, conclusions, recommendations, principles, or even simple studies. Even when the International Law Commission produces ready-to-use draft articles, the General Assembly seems hesitant and leaves them in an eternal legal purgatory (e.g., the Articles on State Responsibility).

Again, I do not think this is necessarily symptomatic of the decline of treaties. Lately the General Assembly has shifted back to treaties as a form of codification: in 2024 it decided to go ahead with negotiations of treaties on crimes against humanity and on protection of persons in the event of disasters. And this phenomenon is mostly proper to codification; it does not necessarily extend to all multilateral treaty-making. In recent years we have witnessed the adoption of momentous conventions: the Paris Agreement on Climate Change, the Treaty on the Prohibition of Nuclear Weapons, the BBNJ Agreement, the WHO Pandemic Agreement, etc.

[17:06] Part 2 – The Real Challenges to Treaties

Santiago Villalpando

Challenge 1: The acceleration of customary law (“high-speed custom”)

The traditional division of roles was straightforward: customary law provided a universal foundation but took decades (sometimes centuries) to form; treaties were the fast way of establishing new rules in writing. In recent years this division has been put into question as customary law has started to form faster and faster – what Bauman would describe as more “liquid”. Already in 1969 the ICJ declared (North Sea Continental Shelf) that the passage of only a short period of time is not necessarily a bar to the formation of a new rule of customary international law. Today customary rules emerge in a matter of years in areas such as disarmament, IHL, environmental law, or cyber law – sometimes quicker than the time it takes to negotiate and bring into force a multilateral treaty (example: many rules of UNCLOS on EEZ and continental shelf were customary by the time the Convention entered into force in 1994).

This is partly due to the intensification of international relations and adjudication (ICJ, ITLOS, WTO, arbitral tribunals, international criminal tribunals, etc.). A mentor of mine, Luigi Condorelli, called this “high-speed custom”.

Challenge 2: The spreading of soft law

We have witnessed the emergence of declarations, recommendations, resolutions, compacts, guidelines, codes of conduct, action plans, frameworks, best practices, etc. These can be negotiated more quickly, do not require parliamentary ratification, and in an international legal order without centralised enforcement, the advantage of speed often outweighs the lack of formal binding force.

The biggest challenge: the combination of high-speed custom + soft law

When soft-law instruments (e.g., GA resolutions, ILC draft articles) are repeatedly cited by courts and tribunals, customary law crystallises without any treaty. Examples:

Universal Declaration of Human Rights → customary human rights;
ILC Articles on State Responsibility → consistently applied by courts;
the plea of necessity in investment law built by back-and-forth citations between the ILC and tribunals.

[24:30] Part 3 – What Is Really Happening: A “Netflix Dilemma”

Santiago Villalpando

If what I am describing is not a decline, then what is it? In my view treaties are facing what I would call a “Netflix dilemma”. At one point Netflix streaming was the disruptive technology that changed how we consume video, forcing the extinction of brick-and-mortar video clubs and quickly acquiring a monopoly. But as time went by other streaming companies emerged, challenged the monopoly, and made some believe Netflix was facing demise.

The same may be said of treaties. There was a time when treaties were the disruptive technology of law-making that could produce new written rules quickly, pushing the old-fashioned custom to the sidelines. If you wanted to outlaw war, prevent and punish genocide, or codify diplomatic relations, there was one sole way: conclude a treaty.

Custom and soft law are now the Hulu and Disney+ of international law-making. They pose a challenge to that monopoly and offer alternative ways of attaining the same purpose. In this context it is natural to have the impression that this might mean a decline of treaties.

The fact is, however, that both Netflix and treaties have adapted to the new environment of liquid modernity in two ways:

by focusing on their competitive advantages;
by adjusting their offer to the new needs of society.

A. Competitive advantages of treaties

Treaties remain the best (sometimes the only) tool when you want to:

create an international organisation;
establish effective dispute-settlement mechanisms;
secure financial commitments;
require domestic implementing legislation (e.g., international crimes);
give smaller states a real voice through multilateral negotiation (Paris Agreement – small island states forcing the 1.5°C target).

B. Treaties themselves have become more “liquid”

Contemporary treaty law and practice has become more flexible than ever:

streamlined entry-into-force (signature or exchange of letters instead of ratification);
consensus package deals instead of voting;
fluid titles (agreements, arrangements, MOUs, joint statements);
long, carefully balanced, “never-ending” provisions (Paris Agreement Art. 7 on adaptation);
patchwork structure (framework convention + protocols + annexes + schedules modifiable by simplified procedure);
individually tailored commitments (opt-in/opt-out, reservations);
evolutive interpretation (subsequent agreement and practice);
frequent amendments (Rome Statute amended 7 times in 20 years);
permanent institutional structures (COPs, MOPs, scientific committees) that keep negotiating forever.

[38:18] Conclusion

Santiago Villalpando

My argument is that the news about the possible death of treaties is greatly exaggerated. Treaties are not declining as a technique of international law. They have rather evolved to adapt to the new liquid environment that characterises contemporary international relations – both by finding their specific role among new competing means of law-making and by adapting their law and practice to the needs of the international community. As Eli Lauterpacht said, they have changed as society has changed.

Before I conclude, let me briefly address a question you might all be asking: “So what? Why does this matter?”

Zygmunt Bauman studied liquid modernity because the erosion of stable social structures brings deep anxiety and insecurity to individuals. A similar sense of anxiety is very present today among international lawyers – challenge to institutions, defiance of established values, perceived erosion of formal commitments.

In such an environment, emphasising the continued relevance of treaties is important because it is to treaties that the international community has always resorted to rebuild international relations after periods of turmoil – from Westphalia to the Congress of Vienna to the Charter of the United Nations. Too often this has only happened after the scourge of war.

Faced with today’s dangers, our role as international lawyers is not only to defend the values on which our global society is built (values that may be changing) but also to convey the message of hope that the international legal order can offer tools to rebuild our world – tools on which we can rely to build back a new sense of stability in a world of liquid modernity.

Thank you very much.