The stench of battle and bloodshed wafting over most of Europe’s history is common to the human experience across our planet. Europe, however, differs from other strategically significant continents in several important ways. The most recent of these distinctions lies in the nature of the security order established there after the Second World War and expanded after the Cold War, founded on the power and engagement of the United States, which now faces potentially mortal challenges. To appreciate this order’s full significance, however, it is worthwhile considering it in the context of other distinctive aspects of Europe’s history.
Some have argued that the very lack of imperial leadership and political unity after Rome’s fall itself stimulated the internal competition and dynamism essential to Europe’s eventual rise and global dominance. In the five centuries after the Ottomans seized Constantinople, European states succeeded in enslaving, colonising or otherwise controlling much of the rest of the world, or seeded powerful new polities that became world powers in their own right, including the United States of America. At the same time, war remained an almost constant presence in Europe itself.
There were some significant diplomatic efforts to maintain peace. After a quarter of a century of revolutionary and Napoleonic bloodletting ended in 1815, there were several decades of relative quiet under the ‘Concert of Europe’, in which the more reactionary states combined to suppress incipient unrest. But this system had collapsed by the middle of the nineteenth century, which saw a flurry of significant wars among the European great powers. The so-called ‘balance of power’ that followed was underpinned by the possibility of a cataclysmic ‘European War’ which leaders knew could erupt at almost any moment, and eventually did in 1914.
Europe is also unique in the fact that, during the twentieth century, its internal struggles provoked both world wars, with their devastating, global and irreparable consequences for much of humanity. The first of these wars arguably – and the second indisputably – represented an ambition by one of Europe’s more powerful states to match its rivals’ international imperial exploits by colonising and dominating its own continent. But the Second World War compounded the misery of the First, ending with much of Europe in ruins, millions of its people murdered or maimed, and its treasuries bankrupt, with the continent effectively divided between the influence of two, essentially non-European powers: the US and the Soviet Union.
While the salvation of Western Europe, at least, was possible thanks in part to Britain’s perseverance, Britain’s own survival and then future role as springboard for European liberation was in turn thanks to the awesome industrial power of the United States. America’s internal and isolationist politics prevented its intervention at the beginning of this new European war, but its president had sought reassurance from Winston Churchill that the fight would continue even if Britain itself fell to the Nazis, and provided his own assurance that Washington would then assist that ongoing resistance. Hence Churchill’s pledge in June 1940 that even if the homeland were overrun, the British Empire would hold out ‘until, in God’s good time, the New World, with all its power and might, steps forth to the rescue and the liberation of the old’. While Britain remained free, the New World did indeed liberate its European progenitors, although not before the US was itself attacked in the Pacific. An earlier intervention, while perhaps politically implausible, might have saved much blood, treasure and suffering.
The next 45 years fortunately remained peaceful in terms of conventional military conflict within Europe, although in strategic terms the continent’s new role was to serve as a chessboard for the non-European superpowers, and their primary battlefield should the Cold War become a Third World War. If a superpower conflict had gone thermonuclear, Europe would likely have been almost totally destroyed.
In more positive terms, the post-war period also saw the emergence in Western Europe of a security order founded upon Washington’s preponderant military and economic power and the notion of collective security across the North Atlantic. NATO, naturally dominated by the United States, was soon accompanied by nascent economic and political European communities, whose overlapping relationship with the Alliance could be both complementary and conflicting.
While significant elements within Western European states, particularly on the Left, chafed at the enduring post-1945 American presence in their countries, this resentment never extended to the level of hatred towards the USSR felt by most inhabitants of the ‘satellite’ states in the Warsaw Pact, for whom the Soviet military and intelligence presence represented an active foreign occupation, most obviously in Hungary in 1956 and Czechoslovakia in 1968. Although the US substantially reduced its forces in Western Europe following the collapse of the USSR in 1991, this was due more to Washington’s desire to enjoy the ‘peace dividend’ than to any unsustainable opposition from European populations or leaderships. Indeed, in the post-Cold War era, despite the disappearance of the unifying common adversary of the Soviet Union, the US-led security order in Europe endured and even expanded eastwards.
Europe’s trilemma
‘Let Europe be whole and free’, proclaimed US president George H.W. Bush in 1989, describing Washington’s ‘larger vision’ for a ‘Europe that is free and at peace with itself’ as the Cold War drew to a close. In an essay published in late 2023, the historian Timothy Garton Ash evaluated Europe’s progress in the intervening decades towards the desired ‘trinity’ of ‘whole, free and at peace’. Of course, this ‘trinity’ – perhaps reformulated as unity, liberty and security – could be applied as an analytic prism to all European history. And on closer inspection, over this longer time frame, it could be understood more accurately as what economists refer to as an ‘impossible trinity’ or ‘trilemma’: one in which the three goals are to some extent in tension, and where it is often impossible to achieve all three simultaneously.
For instance, the unity and security brought by the Roman hegemon were accompanied by a lack of liberty or self-determination. The states of Europe in subsequent generations may have enjoyed more liberty, but they were also more politically fragmented and less secure. Later efforts in the nineteenth and early twentieth centuries to create an indigenous European security order of equal and sovereign states, marked by greater cooperation and even forms of collective security, ultimately failed catastrophically.
It was not until the return of the figurative prodigal son, in the shape of the United States, that Europe was able to enjoy all these goals in conjunction. In effect, both during and after the Cold War, the US served as an historically anomalous form of non-territorial hegemon in Europe. This was far from the ‘offshore balancing’ that certain contemporary ‘realists’ espouse: Washington maintained hundreds of thousands of troops on the continent, along with nuclear weapons, and remained tightly bound to Europe through NATO’s collective-security pact. Yet the US did not occupy or annex European territory, nor did it depose governments within the Alliance which acted against its perceived interests. For example, when, in 1966, Charles de Gaulle withdrew France, one of the major Western powers, from NATO’s integrated military command and expelled NATO’s military headquarters, American tanks did not roll into Paris. Nevertheless, the European security order was indisputably dependent on America’s military (and to an extent its economic) power.
Washington did not perform this role out of self-sacrificing altruism, but enlightened self-interest. It considered the preservation of Western Europe within the free world a key national interest. So was the prevention of further internecine and destabilising European war. The US served not only as a protector against the external Soviet threat but, more implicitly, as a guarantor of peace within Europe. America’s engagement in Europe acted as a crucial reassurance to its wartime allies that it would be safe for West Germany to rebuild and act as a bulwark against communism. America’s enduring presence after 1989 offered additional comfort to Britain and France, both of whose leaders harboured grave misgivings about German reunification. Europe thus enjoyed many of the security advantages of a hegemonic presence, but without the traditional accompanying disadvantages of tyranny or territorial predation.
This reconciliation of the impossible trinity was assisted by the pooling of national sovereignty through increasing European political and economic union, which saw some movement towards increased unity while largely maintaining national liberty. But this brought with it little meaningful increase in indigenously generated security: Europe’s security was still ultimately dependent on the US. A desire for the welcome budgetary relief brought by increasing conventional disarmament after the Cold War, perhaps combined with an overlearning of the lessons of its own destructiveness and self-destructiveness in earlier centuries, saw a succession of disgraceful military hesitancies or impotent performances in Europe itself or its immediate vicinity which required American muscle to resolve – from Bosnia through Kosovo to Libya. Despite these humiliations and countless reasonable demands from multiple US administrations for more equitable ‘burden-sharing’, most Europeans continued to assume that they would be able to enjoy indefinitely the protection and benefits of a relatively benign and liberal Leviathan.
What happens when the Leviathan leaves? Can Europe continue to enjoy the combination of unity, liberty and security if the US either cannot or will not continue to act as its security guarantor?
Ukrainian crucible
The Biden administration has frequently reaffirmed Washington’s commitment to the military support of Ukraine and more generally to the protection of Europe through NATO’s Article 5. But both these commitments are dependent on the vagaries of US politics and the larger structural realignment of US security priorities towards East Asia to confront a rising China. The cold realities of Europe’s declining global significance – European states accounted for 28.6% of global GDP in 1990, but only 17.9% in 2019 – are hard to ignore. The US has largely abandoned earlier aspirations to be able to fight two wars in different regional theatres simultaneously. If it wishes to prevail in a war against China in East Asia, it may reasonably aim to provide military materiel for its allies in concurrent conflicts elsewhere, but not itself to fight on two fronts. Even the provision of that military equipment, however, is vulnerable to shifting domestic politics.
In the first two years of the Russo-Ukrainian war, Ukraine’s defence was heavily dependent on US military aid. In January and February 2024, despite a majority of American voters and their representatives in Congress favouring continued US military support for Ukraine, a small but powerful minority in the Republican Party, under the sway of its likely nominee for the presidential election, Donald Trump, held up the passage of a crucial $60 billion package of military support for Ukraine while Ukrainian forces were forced to ration ammunition. It is possible that, by the time this article appears in print, this squalid episode will have been resolved. But it has underscored that the US and the world face the real prospect of a second Trump presidency in 2025, and that this would prove disastrous for the defence of Ukraine and Europe more broadly.
Trump has demonstrated many times that he does not subscribe to the ideal of collective security. At best, he considers NATO as being akin to an American landlord being bilked by ‘delinquent’ European tenants, at worst something closer to a Mafia protection racket, and he has boasted that he would ‘encourage’ Russia to attack any Europeans not paying their dues. It is possible that this is a cynical attempt both to entertain his resentful supporters and to frighten parsimonious and parasitical Europeans into paying for their own defence. But given that in his first term Trump suggested to his advisors that Washington should withdraw from NATO, and one of his former national security advisors, John Bolton, has declared that Trump would certainly follow through on this threat in a second term, any European assumption of indefinite US support for NATO could prove strategically calamitous. As Bolton put it, Trump’s ‘goal … is not to strengthen NATO, it’s to lay the groundwork to get out’. It remains possible that Joe Biden will be re-elected to a second term, especially if Trump is convicted in one or more criminal trials later this year. But the underlying volatility of US politics is likely to continue, as are the structural pressures forcing American strategic attention towards Asia, whichever president is in power.
Europe therefore faces the re-emergence of an old security threat on its borders at the same time that its security guarantor of the past 80 years is threatening either to disappear or at least to diminish. Russia’s brutal invasion and attempted annexation of Ukraine has thus far proved less successful than feared two years ago thanks largely, at least in its first crucial few weeks, to a combination of Ukrainian courage and pre-war Anglo-American military training and supplies. But the notion of Russia as a prospective partner in the European security order, nurtured by some until quite recently, appears unthinkable for at least a generation. The judicial murder of Alexei Navalny represented the figurative death of any remaining hope that Russia might evolve into a less confrontational and predatory neighbour. For the foreseeable future, any European security order can only be sustainable if it excludes and defends against Russia. This realisation is epitomised in the statements of French President Emmanuel Macron, previously intent on avoiding Russia’s humiliation and retaining a place for it in Europe’s security architecture, who in February 2024 declared that European security in fact depended on Russian defeat in Ukraine. Macron and other European leaders have recently underlined the risk of Russia broadening its attacks against Europe, beyond Ukraine, within a matter of years.
It is important not to understate what European states have so far accomplished. Their shared desire to avoid returning to a Europe of territorial conquest and subjugation means that their unity and resolution to resist Russian aggression has been far greater and more sustained than many feared two years ago. Originally (and justifiably) pilloried for its timidity and desultory levels of military assistance to Ukraine, Germany has since sharply increased its military aid and announced a permanent troop presence in the Baltics. The accession of Finland and Sweden, two militarily capable states, has strengthened the Alliance and marks a strategic setback for Russian President Vladimir Putin. European defence spending increased after the initial shock of Russian behaviour in Ukraine in 2014, then increased further as a result of Trump’s threats and the full Russian invasion of Ukraine in 2022. Kyiv has signed bilateral security agreements with Berlin, London and Paris. In early 2024, as MAGA Republicans blocked the desperately needed $60bn in aid to Ukraine, the European Union overcame a Hungarian veto to provide a similar amount, although this was financial aid to be distributed over the next three years. Most recently, Macron aired the possibility of NATO ground forces defending Ukraine directly, although the rapid declarations from his counterparts across Europe that they would never do so doubtless undermined the deterrent power of his suggestion, which was soon followed by Putin’s threats that NATO forces in Ukraine would produce a direct clash with Russia and the possible use of nuclear weapons.
Europe alone?
A Europe composed of around 30 sovereign states of very different sizes, economic and military capabilities, and strategic perspectives will predictably struggle to achieve unanimity or even consensus on security priorities. This disunity was somewhat sustainable with the American Leviathan acting as a backstop, especially as a federal Europe is in no way a feasible prospect in the foreseeable future. But with the possibility of the Leviathan’s withdrawal within a matter of months, rather than years or decades, it is unclear how far the recent encouraging European rhetoric will be matched by meaningful actions. Decades of underinvestment in defence will require significant and sustained expenditure to remedy, at the same time that anaemic economic growth, costly social models and ageing populations put great pressure on those same budgets.
As we approach the 75th anniversary of NATO’s founding, much will be heard of its status as the most powerful alliance in history. Probably less will be said, at least in public, of the reality that its members remain overwhelmingly militarily dependent on a single ally, and even less about how Europe would feasibly and sustainably secure itself during a second Trump presidency. Before America’s presence on the continent, Europe had never developed a sustainable indigenous security order that allowed it to reconcile the trinity of liberty, unity and security. It is unlikely it would be able to do so now if it found itself once more without America. We are unlikely to see the emergence of a new, indigenous security-providing hegemon that would not be strongly resisted by others. We may observe increased fragmentation of European efforts, and the increasing regionalisation of security cooperation based on geography and alignments of security perceptions. If there were a full and dramatic US retrenchment from Europe, it is conceivable that a number of European states (notably those nearest Russia) could begin the process of acquiring nuclear weapons. In the shorter term, we might see efforts to develop European nuclear-sharing arrangements, although it is unclear whether Eastern European states would have more confidence in the extended deterrence provided by France or Britain than that by Trumpian America. Increased federal unity is also unlikely, although European states will ultimately need to find a way to secure themselves against larger and more cohesive entities such as Russia and China, while at the same time preserving their own liberty. But necessity is not always the mother of invention.
In the first volume of his monumental history of the decline and fall of the Roman Empire, Edward Gibbon remarked that ‘if a man were called to fix the period in the history of the world during which the condition of the human race was most happy and prosperous, he would, without hesitation, name that which elapsed from the death of Domitian to the accession of Commodus [96–180 CE]’. It is striking that these 80-odd years in the second century CE, the height of the Pax Romana, might appear to be not only a golden age, but Europe’s happiest period thus far as late as 1776, when Gibbon’s first volume was published. It would have been impossible, though, for Gibbon to have fully foreseen the long-term consequences for his own continent of the momentous developments taking place that same year across the Atlantic. The birth of the United States of America, and its ultimate role as a security provider, allowed for a period in Europe when relative unity, security and liberty were concurrent and whose happiness and prosperity far outshone that of the second century. It may be that our distant descendants, like Gibbon, will consider the 80-odd years of the Pax Americana in the post-war – and especially the post-Cold War – period as a brief aberration in Europe’s long history of bloodshed, and itself a golden age long lost.