From Thucydides to Trump

The theories and thinkers behind a return to Great Power brutalism

As we all reel at the suddenness and depth of America’s turn away from its post-war policies, then there’s inevitably increasing focus on what it means for our future. In doing that I believe it also helps to look to the past, humanity’s long history of global conflict and what previous thinkers have to tell us.

Firstly though, anyone who thinks Donald Trump has a theory of international relations clearly hasn’t been following him very carefully. He is instinctive not thoughtful, and has a mindset driven by his own pathologies and business practices, which he has extrapolated into how he wants to rule the world.

All the same – however he arrived where he has, and whether he realises it or not – he is still operating within a framework about the US’s place within the world and how it should operate within that framework. And even if Trump doesn’t understand or care about such theories or intellectual constructs, others do.

Even more to the point, they use that thinking and related understandings to formulate and drive a coherent foreign policy over time. They would consider that gives them an advantage over an opponent who thinks with their gut. I think they’re right.

So international relations theory and thinking matters, and the recent Trump pivot marks a major shift in the US approach to the world.

Anyone kind enough to read my substack will already have read some remarks on this from me as part of wider comments. However, I have also recently been asked by a number of people about the background to terms like ‘Great Power politics’ and the ‘Rules Based International Order’. So, I thought I would write something on my (non-academic) understanding of what they mean.

The lessons of Ancient Greece still resonating today.

To start then, we should go back to the Greek historian, Thucydides. He wrote one of the great works of ancient history, The History of the Peloponnesian War. Relating the 27 year war (431-404 BC) between the Spartan and Athenian alliance, the history has had a lasting influence to this day.

In particular, we have the so-called Melian dialogue, containing the following much-quoted sentence (including by me in my presentations for almost a decade): “…you know as well as we do that right, as the world goes, is only in question between equals in power, while the strong do what they can and the weak suffer what they must.”

This is perhaps the seminal statement of the international relations theory of political realism. Those with power use it to their own narrow ends, while the weaker have to suck it up. It’s useful to look at the example Thucydides used to come to this conclusion.

Melos was an Aegean island, seeking to remain neutral in the Sparta/Athens war. To cut a long story short Athens said it couldn’t afford to allow them to stay neutral, so they should surrender, pay a tribute and live on in relative peace. In the negotiations that followed the Melians say they are not a threat, so surrender is neither fair nor necessary. The Athenians basically tell them the world runs on big boys rules, so get real, or else, hence the quote above.

The Melians opted for ‘or else’, and after a brutal siege surrendered, following which the Athenians executed the fighting age men and enslaved the women and children. Point proved.

In a less-used quote, the full cynical perspective on the nature of global politics, and indeed human nature, comes through: “Of men we know, that by a necessary law of their nature they rule wherever they can...all we do is to make use of it, knowing that you and everybody else, having the same power as we have, would do the same as we do.” Everyone’s as bad as each other given the chance.

This view of international relations, elaborated over the centuries by later thinkers, was not just based on the bigger powers calling the shots, but the nature of the world order and what actually mattered – defining the critical interests that nations were competing over.

Thus, the proponents of this world view assumed a basically anarchic global order, where dog ate dog, and everyone operated to a purely national interest to survive and if possible prosper.

Great Power competition and ‘Realism

In the view of such thinkers those interests were also defined quite narrowly to military and economic power – basically values-free. Alliances were transactional and temporary, according to convenience. Britain’s 19^th century Prime Minister is famously quoted as telling parliament in 1848, “We have no eternal allies, and we have no perpetual enemies. Our interests are eternal and perpetual, and those interests it is our duty to follow.” Of that, more later.

In international relations this theory and thinking is known as the ‘realist’ school and would broadly include historical figures such as Thomas Hobbes, Machiavelli and Clausewitz. In the 20^th century it remains highly influential but, as is the nature of such things, has spawned off-shoots such as ‘neo-realism’ and ‘offensive realism’.

All basically see an anarchic world order, with competing Great Powers, whose dangerous competition is often only stabilised by the spheres of influence they dominate.

It’s of interest that one of the most prominent current realists – the main proponent of ‘offensive realism’ – John Mearsheimer, has been a strident critic of western support for Ukraine. He has blamed us for the conflict, and says Ukraine should accept being in Russia’s sphere of influence, not seek its own path, stating "This is a dangerous way for Ukraine to think about its foreign policy choices. The sad truth is that might often makes right when great-power politics are at play.” Pure Thucydides. Also, it’s no surprise that the Kremlin are great fans of Mearsheimer.

But if Great Power competition has dominated international relations for much of history, is it eternal, and also so bluntly restrictive in its view of what national interests matter?

I should say at this point that I have always noticed that cynics tend to describe themselves as realists. Leaving aside its inherent gloominess, why is a cynical mindset any more realistic than an optimistic mindset?

Is there an alternative to dog eat dog?

That brings us to another perspective – one, amongst other things, driven by the rise of modern democracies and latterly globalism. Its proponents challenge both the inevitability and necessity of Great Power competition and also the narrowness of what the realists define as critical national interests.

These alternative schools of thought and approaches to international relations are more idealistic and could be broadly labelled as ‘liberal’ or ‘constructivist’, and this kind of approach is what lies behind the so-called ‘Rules Based International Order’ (RBIO) which has been highly influential since the end of World War Two. Most notably those rules have been expressed through the UN Charter, signed up to and agreed by, amongst others, the USA and Soviet Union.

The Charter and the very creation of the UN is itself a continuation, develop and expansion of conventions and treaties largely dating from the latter part of the 19^th Century. They include, to name but a few, the Hague Conventions of 1899 & 1907 on the laws of war; the creation of the Red Cross along with various Geneva Conventions on international humanitarian laws dating from 1864; the 1997 Chemical Weapons Convention, banning chemical weapons.

But this rules-based order goes far wider than just warfare. They include: The World Trade Organisation (WTO) replaced the 1948 General Agreement on Tariffs and Trade (GATT); the UN Convention on the Law of the Sea (UNCLOS); and of course, innumerable bilateral agreements between countries over trade, borders and much else. And then there are groupings such as the EU and NATO.

So, the rule-based order is very much the story of the post-war world. Partial, by no means always fair or fully applied, but still very real and to huge effect. Equally to the point, it has been to a large degree accepted and respected by the great powers. Indeed, the ultimate superpower, the USA, was the primary driver in the creation of much of the RBIO.

But there are two other elements that marks a key difference with the hard-eyed viewpoint of the supposed realists. Firstly, enlightened self-interest. Not simple charity, but a view of the world that saw big and small could individually gain more through co-operation than competition and that needed a common set of rules.

The other element is a much different and expanded perspective on what the national interest is – what matters and what motivates. In general terms the realists talk about hard power and economics. This is challenged by other schools of thought, especially supporters of constructivism. They argue ideas and values also matter in nation’s judgement and influence their actions. In particular we seek and support allies who share our values.

If all this seems a little theoretical, it’s not. It’s very, very real.

And values have value, even if they don’t easily fit into a balance sheet.

Why otherwise would there be a NATO, that saw the now 30 nations of NATO combine their military forces to defend each other? An Alliance, for instance, that sees Britain, over 1500 miles and the channel away from Russia, send troops to Estonia, and be prepared to go to war with Russa if Estonia is attacked.

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Is the US really a sucker and are we just freeloaders?

It’s absolutely fair to say the US has carried too much of the burden of defending Europe, and indeed the free world, but it has also benefitted hugely.[i]

When it went to war in Afghanistan and Iraq, very few other nations really wanted to join in, but they did all the same, and paid the price in blood as well as treasure and often electoral unpopularity. In its Great Power competition with the Soviet Union, Europe provided the bases. When it bombed Libya in 1986, its planes flew from Britain. US intelligence is massively enhanced by the ‘5 eyes’ sharing with Australia, Britain, Canada and New Zealand. Its leadership in NATO was repaid with support from the West in so many areas, extending far beyond just security. A shared outlook and values as well as a sense of obligation aligned the West behind the US – it was not a simple one-way street.

So yes the financial balance sheet is unbalanced in some areas, but America has hardly been a sucker, as Trump claims – the 20^th Century was not rightly proclaimed the ‘American Century’ for nothing. Neither is America poor. Indeed, the prosperity generated in the era of RBIO has disproportionately gone to the US, even if it was badly shared once it got there.

Even in the 19^th Century, an era when Great Power competition was at its most obvious, the idea that values and putting them into effect had no role in foreign policy was rejected. I have already quoted Palmerston saying in 1848, “We have no eternal allies, and we have no perpetual enemies. Our interests are eternal and perpetual, and those interests it is our duty to follow.” However, in the same speech he also said, “I hold that the real policy of England… is to be the champion of justice and right, pursuing that course with moderation and prudence, not becoming the Quixote of the world, but giving the weight of her moral sanction and support wherever she thinks that justice is, and whenever she thinks that wrong has been done.”

Self-serving? Maybe to some degree, but still a recognition of the role of ideology and values in foreign policy. In this century RBIO’s advantages have been well spread, but the US, as prime instigator, has been a prime beneficiary.

From a unipolar to multipolar world

It could do this because it was, firstly, the leading Great Power, and then over the last three decades the only superpower, a sort of global policeman. This unipolar world could not last and, leaving Trump aside, the move to a multipolar world was inevitable as other powers rose.

Most obvious of course is China – already a serious competitor at all levels, whether security, soft power or economic – but also more aspirational rising powers, often currently regional, such as India, Saudi Arabia and Turkey.

And of course, there’s Russia, with Putin’s narrative openly relishing the end of Western – by which he means American – unipolar dominance, claiming in one speech last year, “We can frankly say that the dictatorship of one hegemon is becoming decrepit. We see it, and everyone sees it now.” In a later speech he said, “We are witnessing the formation of a completely new world order, nothing like we had in the past, such as the Westphalian or Yalta systems.”

Dangerous times then, and we can again turn to Thucydides for a pithy summary of the risks from shifting balances of power when, describing the origins of the Peloponnesian War, he said, “It was the rise of Athens and the fear that this instilled in Sparta that made war inevitable.”

The battlelines are drawn

There in broad terms, are the battlelines. A world in flux with a contest between Great and Rising Powers competing for dominance, and the RBIO, the Rules Based International Order.

Fighting for the RBIO is a distinctly uninspiring battle cry, and I have always preferred this simple summary from a former Norwegian Prime Minister, Erna Solberg, who said in 2016, in the aftermath of the first Russian invasion of Ukraine in 2014, “We cannot have a world where big countries decide what to do with their neighbours.”

How to defend that kind of RBIO has been the dominating theme of NATO and many other international discussions for two decades, and a rising sense of threat.

But in those discussions what wasn’t predicted was the seeming 180 degree turn by Trump. There was real concern, even a little fear, about the level of his commitment to NATO, to Ukraine, and many other elements of US foreign policy, but not what looks like an actual switching of sides, and that’s what we have seen in the last two weeks.

When the US votes against a UN motion condemning Russia’s invasion of Ukraine and Trump mouths Russian talking points while calling Zelensky a dictator this is more than symbolic. His casual offhand denial of saying he’d called Zelensky a dictator a few days before only adds to the sense of disconnect and shifting sands.

Taken along with a raft of other actions and statements Trump and his representatives are signalling a break with 80 years of leadership, policies and an abandonment of a certain kind of values-based approach.

As stated at the beginning, Trump has no grasp or interest in international relations thinking – there is and will be no Trump doctrine. However, by temperament he is a hardline Great Power kind of guy. He lives in a zero-sum world where there are only winners and losers. Also, winning and losing is defined in the only thing Trump understands, which is hard cash. What America has gained from the American Century can in part only be expressed in intangibles, and is based on shared values and mutual benefits.

Trump’s world view is amoral and value-free, and his simplistic art of the deal is to say ‘what’s in it for me’, and ‘what’s in it for us’ is alien to his mindset. His lack of empathy and self-awareness is exemplified by his remarks on the mineral deal being planned with Ukraine and recovering the cost of the help already given, “We want to get that money back. We’re helping the country through a very, very big problem… so we have to straighten it out, but the American taxpayer now is going to get their money back, plus.”

Is there anything more contemptible than the leader of a rich country not just demanding payment to help a democracy under attack, but wanting to make a profit – and then boasting about it?

But that is the reality, as is Trump’s sense of fellow feeling with dictators, and his disdain for the rules-based order his country led in creating, already being shown by his willingness to ignore it.

In my 25 years in NATO the contest between the RBIO and to prevent a return to Great Power competition, where might trumped right was real, not theoretical. At one stage there seemed grounds for optimism, but certainly not today.

I think it is somehow symbolic that in raising defence spending Keir Starmer funded it from the aid budget – soft power funding hard power seems an apt metaphor for the return of hard-eyed Great Power conflict, even if dismissing the value of soft power is arguable.

Regardless, as the sun seemingly sets on the RBIO, we are in huge danger of returning to the world of Thucydides – one where the ‘strong do what they can’, while the institutions such as NATO created to prevent ‘the weak suffer(ing) what they must’ look to be in some jeopardy.

Moreover, we had assumed that in any Great Power competition, we had ‘our’ Great Power, the US. We can no longer assume that. At best, it’s clear a price will be demanded, and the intangibles alliances offer won’t cut it. At worst, the US may not even be on our side, and cannot be consistently trusted. Additionally, we now live in a multipolar world of rising powers with their own interests. Even with the US onside we would be living in a far tougher neighbourhood.

All is not lost. To some degree we are the authors of our own misfortune because we did not pay the insurance premium needed to guard against a change in the international weather. Whatever the current stresses we remain rich nations and we still have huge resources to draw upon – as long as we change our mindset, recognise the scale and nature of the challenge and rise to it.

The world has changed and it’s going to require painful sacrifices, but how weak we are and how much we must suffer is still in our hands.

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[i] It does not excuse Europe’s lamentable underspend to highlight that the US’s defence budget is far from all spent on Europe or NATO. As a global superpower only a portion is committed to NATO and much of the 3.4% of GDP it spends on defence goes elsewhere, for instance in Pacific Command in (legitimate) support of its own national interests. As an example, in February 2025, of the eight Carrier Strike Groups or Amphibious Ready Groups, only two were in NATO’s area of operations.