The quest for absolute sovereignty – the aim of many Brexiteers – is not the way to maintain peace in Europe, writes Beatrice Heuser (University of Glasgow). The EU is not perfect. But nothing suggests that Britain will be any better off outside it, and its departure will weaken the remaining members.

At the age of 60, the present European co-operation structures have so far demonstrated less longevity than the Roman Empire which (counting from the annexation of the first province, Sicily, in 241 BC) survived for almost 1700 years; or Charlemagne’s Empire and its Holy Roman successor, which existed in some form for 1000. Moreover, the European Communities would not have been so successful had they not been underpinned by the firm commitment to the defence of most of its members that were also in NATO, by the United States, and also by Britain that kept NATO together in times of crisis. And nothing is more conducive to solidarity than a strongly and commonly perceived external threat, which in the Cold War seemed to be posed by the USSR and the client states it had marshalled in the Warsaw Pact. Nor is the EU beyond perfectibility. In its essence, however, it is above all the answer to Europe’s internal security problems.

The circles that had to be squared to give Europe internal ‘tranquillity’ were how to create a Pax Augusti, without an enforcement mechanism, an Augustus, a universal monarch, who even as benevolent dictator would be resented by his rivals; how to preserve the freedom of action, the sovereign option of self-defence of the individual member states, while curtailing their ability to attack others; how an ever larger number of members could take decisions collectively without clogging up the decision-mechanism by vetoes.

The quest for absolute sovereignty that can be traced back to the twelfth century if not to Aristotle is not the answer: one power’s absolute sovereignty is another’s absolute insecurity and one power’s sovereign right to use war as an instrument of it policy is another’s sovereign right to attack it. Neither furthers stability. Sovereignty, and that is the lesson of the Holy Roman Empire, can instead be shared at several levels. Subsidiarity – the principle that decisions should be made at the lowest level possible – was widely practised even there. After these two-and-a-half millennia of experiments with state systems, is seems clear that bilateral quarrels can more easily be resolved by bringing in other parties who have a common interest in a peaceful settlement. A permanent council and parliament of representatives of the states of Europe are essential to replace ‘war war’ with ‘jaw jaw’, to echo Churchill’s catchy phrase. The coincidence of great power interests is not a reliable enforcement mechanism, and that there are few reasons why smaller powers should trust the great powers not to put their own interests first; it is in their interest that not just a great power Pentarchy, but representatives of all nations should have voting rights in the decision-making forum.

It is hard to prescribe complete disarmament or even only a reduction of armaments on all sides, and mutual limitations on sovereignty, on the ability to go to war unilaterally. But structures allowing for multilateral consultation are all excellent inventions of the past that will be of great use for the future if they survive, and if the EU is not torn apart by divergent priorities and the resurgence of national selfishness. The legal acquis of the EU, the adoption of a European Charter of Human Rights, are remarkable achievements that would have satisfied the jurist Johann Kaspar Bluntschli. A return to balance-of-power competitions and rivalries, to sovereigntism, to nationalism and empire-building with the many wars they brought, and the return to laws and standards applying to one medium-size polity only, do not.

All this suggests that the EU is the least bad state system Europe has known, despite its many flaws and shortcomings. Or to paraphrase Churchill, it is the worst form of government for this continent except for all the others that have been tried. In many areas it is in desperate need of reform. The idea of a strongly federated core Europe surrounded by more loosely confederated states, as proposed by Karl A Lamers and Wolfgang Schäuble, was the best recent proposal by far, and deserves to be reconsidered. Nothing suggests, however, that from a security point of view, any individual state of Europe will be better off outside this EU and its consultation mechanism, its burden-sharing and its economic support for weaker powers, which in the long term through prosperity can help stave off intra-European mass migration and radicalism. Just as the rich are never entirely safe from robbery or revolution as long as their neighbours are poor, rich countries enhance their own security by aiding less prosperous ones.

In this context, the sovereigntism espoused and defended by the British Brexiteers is no more conducive to British or European security or the long-term banning of war from the Old Continent than was the proud pursuit of sovereigntism by the French and English kings and the British governments of previous centuries. The absence of war from Europe, the protection of the human rights of its inhabitants, and not only questions of free trade are at the heart of the European project – how would these priorities not also be the core priorities of any British government? What sense does it make to try to achieve those on a ‘national’ basis, given all we have said about the illusionary concept of the ‘nation-state’?

It is difficult to see what past role could serve as a model for the United Kingdom outside the EU: the counter-balancer of which power? The transatlantic hinge without being connected up with the European wing? The head of an ever less significant Commonwealth? The great colonial power and exporter of industrial goods to its colonies which it long ceased to be? The exporter of financial and insurance services, when it refuses to meet the standards of the EU? A world-policeman as a member of the UN’s Pentarchy, when it has long been stripped of its empire as force multiplier and needs partners for all but its smallest security operations? How can the United Kingdom continue to justify its seat on the UN Security Council when in the recent past, Britain like France has told European partners that having two European seats on the Council is better than one EU seat?

What is not difficult to recognise is that the EU will emerge weakened militarily and in other aspects of its security by the withdrawal from it by Britain. It is after all one of only two larger European powers with an unbroken tradition of the use of force to counter aggression, genocide and other major crimes. The other, France, cannot shoulder this responsibility alone on behalf of all the EU, and we see too much historical baggage still today for anybody to be happy with Germany beginning to pull its weight, quite apart from the hard-wired anti-use-of-force reflexes stopping her. Meanwhile, the EU desperately needs new ideas to work out how to influence, without force, the politics of member states that are drifting back to nationalism and authoritarianism and away from post-nationalist ideals of democracy and human rights. All of Europe’s old states face ideological threats from within, from parties and movements far too reminiscent of the radical parties that sprang up in the 1920s and 1930s for anybody to feel complacent about Europe’s political future. Perhaps more than ever, Europe needs all hands on deck, including the experience and patience of old, stable democracies. The major events in European history suggests – whether this be the great invasions starting in late Roman times and ending with 1066, or the ideological/religious wars of early modern times or of the twentieth century, or threats emanating from expansionist powers in Europe – that the major storms of continental Europe also ravage Britain.

In short, however one defines security, whether in narrow military terms vis-à-vis external threats, or whether one includes major domestic challenges, mostly shared across the EU countries, the British exit from the EU would diminish the security of Europe as a whole. Core contemporary British values such as the maximum protection of the individual’s rights and freedoms and policy-making through consultation and co-operation stem from and are still shared with Britain’s European partners, not with Russia, not with China. Ultimately, whatever its political choices, the British Isles and their security are part of Europe’s.

This post represents the views of the author and not those of the Brexit blog, nor LSE. It is an extract from Brexit in History: Sovereignty or a European Union? (Hurst, 2019).

Beatrice Heuser is Professor of International Relations (Politics) at the University of Glasgow.