Whatever else it has been, the argument over Brexit has been a reminder of the way European politics used to be: divided parties; vacillating leadership; unstable governments; intense anger; and the looming possibility that the last word might belong to ‘Citizen Browning’ (as, around 1900, French anarchists called the gun). In this sense, modern British politics has become the politics of old Europe, which between 1848 and 1968 could usually be relied on to supply a stream of congratulatory comparison between British stability and European chaos. British politics now looks more like that of Weimar Germany, postwar Italy or the France of the Third and Fourth Republics. It has become quite hard to believe that for much of the 19th and 20th centuries the properties of the elusive British constitution were a subject of sustained, serious and intense intellectual inquiry.

One of the outcomes of those inquiries was the realisation – which helped to form the European Union – that political problems cannot always be solved by political means, but sometimes have legal, economic or administrative solutions. Political solutions can magnify political problems because politics calls for choices and decisions even if choices and decisions are in short supply. Injecting politics into political stasis can be self-defeating because, as the argument over Brexit has shown, a lot can happen between the initial choice and the final decision. In the interim, almost anything can become political. This is because politics – unlike, say, religion, music, economics or sport – does not have a determinate or pre-given content. The nearest approximation is the idea of the rule of law. But when the rules run dry and the laws wear out, politics will still be there and its effects will still, at the least, be unpredictable. This was the realisation that began to take hold in Europe after 1848 and, more intensely, after 1917 and 1933.

The content of the realisation grew out of the problem of explaining, on the one hand, British social and political stability, despite the very deep economic divisions and fierce social conflict of much of the 19th and 20th centuries; and, on the other, European social and political instability, despite the growing number of institutions and arrangements – such as party politics, a democratic franchise, the separation of powers, an independent judiciary and a free press – that were usually taken to be largely responsible for the British capacity to manage peaceful social and political change. The more institutionally and constitutionally similar the two seemed to be, the more difficult it was to explain the differences in their social and political histories.

After 1848, theorists had three insights that added up both to a powerful explanation of how, in democratic conditions, it was possible to combine political stability with political reform, and, more broadly, to a powerful analysis of the properties of a federal political system. From this perspective, the fabled, famously unwritten British constitution was not something to be set against the centralisation, remoteness and unaccountability of its European counterpart, but the prototype from which the idea of a European Union emerged. In other words, the European Union was the real triumph of British politics, just as Brexit now threatens to reinstate the politics of old Europe in the place once taken to be a living embodiment of the alternative.

The first of these insights was that the British system of government was far more like a federal system than it appeared to be. Not because there was something federal about the United Kingdom of England, Scotland, Wales and Ireland – a type of union more imperial than federal. Rather, the federal side of the British system was supplied by trusts, corporations, syndicates, universities and limited companies. This cluster of institutions not only pointed towards an aspect of the British system of government that has now been largely forgotten. It also highlighted something not usually associated with the idea of a federal system and, by doing so, helped to throw a different light on the idea of a federal system itself.

The initial claim about the relationship between trusts, corporations and the underlying causes of British political stability is usually associated with the thought of the late 19th-century English historian and legal theorist Frederick William Maitland, but it began life a little earlier with the French economic and legal theorist Félix Esquirou de Parieu (the advocate, in the 1860s, of a common European currency). Both Maitland and Parieu described the scale and ubiquity of the network of trusts and corporations in British economic and social life, and the way they offset the more divisive consequences of economic inequality and the democratic deficit. Maitland’s evaluation of trusts and corporations supplied one of the components of what came to be called pluralism, with its emphasis on multiple associations and decentralised government. Parieu focused less on trusts and corporations themselves than on the characteristics of a state that housed a wide array of such political, legal and economic institutions.

A federal system is, simply, a unit made up of smaller units. Since the smaller units were parts of larger units, but were also responsible for providing a range of more or less costly public services and amenities, such as roads, bridges, schools, hospitals, policing, parks or playgrounds, credit would be built into the workings of the whole system. (This was the second insight.) The multiple outgoings of the different units would be funded by a mixture of local and national tax revenue, whether direct or indirect, and the leads and lags in income and expenditure would be covered by public debt. The network of trusts and corporations, with their legal provisions on what they could or could not do with their assets, would reinforce the nexus of debt, income and expenditure and, at the same time, lock public and private finance into a single, loosely integrated system.

In this financial setting, the law – this was the third insight – would have a double identity. In one guise it would be public law, or the system of rules that applied to the membership of a given unit, from a charitable trust to a sovereign state. In another guise, it would be private law, or the system of rules that applied within the membership of a given unit, all the way up to a single state within an international system. In the first guise, the function of the law would be largely positive, to define and enforce a determinate set of rules. In the second guise, its function would be largely negative, to maintain the ability of its subordinate components to define and enforce the law. Just as, in the financial system, the line separating private credit from public debt would be clear but passable, so too, in the legal system, would the line separating public from private law. This was once claimed to be the hallmark of the British system of government, and it became the hallmark of the European Union.

Nothing of this has been seen or heard in the long argument over Brexit. The futility and fatuousness of ‘project fear’ on one side has been matched only by the fantasy and fecklessness of ‘taking back control’ on the other. Historical memory is a slippery thing and its contents are as easy to distort as to forget. (This, it could be said, is why we need historians.) Putting Brexit in its historical context helps to show the scale of what will be lost, not only in Britain but in Europe. It also helps to show what can be gained. The European Union began as a British solution to a European problem. There is still time to take back control and make it a British solution to a British problem.