The “Free Right to War” that Did Not Exist

In textbooks on the history of international relations or international law, materials on political education or in popular documentaries, the same thesis appears repeatedly: the modern world order was born in the 20th century when, in light of the experience of the two world wars, the ban on war was codified under international law. Previously, so the thinking goes, war was a legitimate political tool that sovereign states could use at their discretion. In terms of the decision for or against war, the 19th century was therefore a century of anarchy. But is this assumption accurate?

In his book, Hendrik Simon took on the task of checking this conventional wisdom: Where does the notion of a “free right to war” come from – and can it be substantiated?

When I first came across the thesis of the free right to war, I asked myself: Why doesn't anyone bother to check this thesis and see? Is it actually true?

Hendrik Simon, PRIF Talk 009

According to this widespread belief there was an “old” international order before 1920 – the era of anarchy – and a “new” order that emerged in the context of a radical transformation in the 20th century. It was only with the founding of the League of Nations, the Kellogg-Briand Pact, and finally the UN Charter after the Second World War that war was finally outlawed as a political instrument and a general ban on the use of force in international relations was introduced. This idea is so omnipresent that the footnote with evidence of its prevalence fills an entire page in Simon’s book.

To test the thesis of the “free right to war,” Hendrik Simon draws on the analysis of historical war discourses, in particular justifications of wars and their assessments. These justifications—and the extent to which they were or were not accepted by other states, institutions, or national publics—reveal what was considered a norm at a given time; for example, when and under what circumstances war was regarded as a legitimate measure.

Against simplistic views of the ‘age of anarchy’, Simon argues that during the 19th century — as indeed throughout all history — war required justification. Even if some monarchs, such as Wilhelm II, may have had little love for norms of international law, not a single state claimed a “free right to war” for itself on the international stage. Key concepts shaping the modern discourse on war, such as the idea of the nation or the sovereignty of the people, had already begun to take shape during the French Revolution.

Even the institutionalization of the prohibition of war goes back much further than the 1920s. The Congress of Vienna, which convened from 1814 to 1815, gave rise to the European Concert of Great Powers, which from then on had the authority to judge war. During this period, international violence was only considered justified if the Concert of Powers authorized it or deemed it legitimate. There was therefore no anarchy in the decision for or against war. On the contrary, the modern prohibition of war was already beginning to emerge, even if it was not yet enshrined as such in an international treaty.

This prohibition of war was then further differentiated over the course of the 19th century. For example, it became established that a war could only be justified if diplomatic means of settling the conflict had been sought beforehand.

However, this pacification of Europe through law also had its downsides. The peace of the great powers was accompanied by coercion against smaller powers and the suppression of national and liberal movements. And it was only made possible through colonialism and imperialism in the first place. In other words, peace was bought with violence against people outside Europe.

The 19th century was not an anarchic counterpart to the modern international order but was in fact the era of its birth.

Hendrik Simon, PRIF Talk 009

Yet the question remains: how did the narrative of a “free right to war” become so powerful? According to Simon, the idea goes back to legal scholars close to the military in the German Empire, who argued for political reasons that war was a “natural reality” and that sovereign states were allowed to enforce the “law of the strongest” – a narrative that is central to the realist school of thought. However, this opinion was not shared by legal scholars in other European countries and instead represented a German anomaly. In the Third Reich, the idea was taken up and further strengthened by Nazi jurists such as Carl Schmitt and Wilhelm Grewe.

Between and after the world wars, the minority opinion that a “free right to war” had prevailed in the 19th century was eventually universalized as a supposed fact in the historiography of modern international law – and not only by authors belonging to the realist movement, but remarkably also by liberal jurists. The latter had an interest in presenting the achievements of international law since 1920 as particularly progressive. The idea of the 19th century as a “century of anarchy” helped to make the contrast appear particularly clear.

Ultimately, this leads to the result that, paradoxically, two schools of thought that are actually completely opposed to each other, i.e. realism and liberalism, at least when it comes to the question of justifying war, meet in the same, in my view clearly wrong, doctrine.

Hendrik Simon, PRIF Talk 009

Overall, the book impressively illustrates the long history of the prohibition of the use of force under international law and the rules-based international order. Noting this, reviewers have described the book as being “indispensable for any engagement with the question of how wars are legitimized” (Hubert Zimmermann, Politische Vierteljahresschrift) and “undoubtedly to become a point of reference for debates on the intellectual sources and blind spots of the discipline of international relations” (Eric Sangar, Perspectives on Politics). By dispelling assumptions that have long been taken for granted, Simon reminds his readers to remain critical in their approach to historical narratives and to think beyond conventional patterns and black-and-white explanations. (lfr/ewa)