Despite an increasing interest in the history of blockade in the last decades, surprisingly little is still known about the planning, implementation and the short- and long-term effects of blockade in the first half of the 20th century. The two-day conference aimed to close this research gap and to investigate blockade as a global event not only from economic, diplomatic and military but also from legal, social and cultural perspectives. It brought together scholars to debate current research trends and stake out the ground for new research. Special attention was paid to national and transnational learning effects and how the ‘first blockade’ (1914-1919) affected interwar policies and shaped the ‘second blockade’ (1939-1945). After a brief introduction by JONAS SCHERNER (Trondheim) and ELISABETH PILLER (Freiburg), ALAN KRAMER (Dublin) elaborated on the intentions and the focal points of the project.

In his opening lecture on “Grand Strategy and Blockade”, HEW STRACHAN (University of St Andrews) demonstrated how concepts of siege and economic warfare and the formation of international maritime law and military strategies (Clausewitz, Delbrück, Corbett, Fisher) in the 19th and early 20th century created the framework for the First Blockade. According to Strachan, the actual blockade turned out to be more difficult to implement than expected. It proved to be most effective not on Germany but in the eastern Mediterranean and the Middle East. The aftermath of the First World War saw the development of a number of politically influential narratives: in Germany, the alleged impact of the ‘hunger blockade’ on German morale, and in Britain, a widespread belief that the blockade had been a uniquely successful weapon. Based on these narratives, British and German (but also Japanese and Italian) war planners began to prepare for future blockade. In the Second World War, economic warfare became even more important, as blockade was paired with strategic bombing. The economic consequences were devastating for all but the United States.

GABRIELA FREI (Universität der Bundeswehr Munich) opened the first panel on “Britain and the Blockade in the Era of the First World War”. She turned back to the British “blockade by other means” during the Second Boer War, which in many ways foreshadowed the blockade of the First World War. The British government ruled out a direct blockade (of Delagoa Bay), but adopted a wide range of trade controls and restrictions that, as Frei made clear, would lay the foundation for a broader understanding of blockade as a complex system of trade control. AVRAM LYTTON (University of Calgary) contrasted British pre-war planning with the actual implementation of the blockade after 1914. Lytton noted that rooted in Britain’s own fears of shortages, hence projected onto Germany, British blockade plans were purely maritime in nature and based around food. During the war, Lytton argued, the maritime conception of blockade gave way to a more continental conception of economic warfare that took Germany’s access to vast east European resources into account.

In panel 2 on “Global Blockade and the First World War, Part I”, SAMUËL KRUIZINGA (University of Amsterdam) moved away from the focus on British blockaders and emphasized Dutch and Spanish involvement in trans-blockade food aid to German-occupied Belgium and Northern France. With the US entry in the war in April 1917, the relief of Belgium passed into the hands of the hitherto little-known neutral Comité Hispano-Néerlandais, which, Kruizinga showed, pursued its own interests and used its information advantages to play off the British blockaders and the German occupiers against each other. Both the Dutch and the Spanish governments insisted on retaining a decision-making role regarding food aid to Belgium; moreover, the CHN maintained a high degree of autonomy and exerted effective pressure on the German occupation regime. TERESA NUNES (Universidade de Lisboa) dealt with the interests of Portugal during the First Blockade and how Portugal sought to survive the war with its overseas empire intact. Neutral Portugal had to face conflicts of interests related to its colonial possessions not only with Germany but also with Britain. However, ultimately, Nunes argued, it used the blockade as the opportunity to go to war in 1916 on the Allied side.

In panel 3, “Global Blockade and the First World War, Part II”, MARCEL BOLDORF (Université Lumiere Lyon) dealt critically with the ‘hunger blockade’ and German claims of starvation by the Allies. He showed the multiple reasons for food shortages in Germany during the First World War and contrasted them with the alleged effects of the ‘hunger blockade’. While the blockade did have an effect on the German food supply, particularly due to shortages of fertilizer, it was not the key reason for German hunger. German claims to that end were meant to distract from home-made economic problems. Drawing on the practice of unilateral sanctions today, PHILLIP DEHNE (St. Joseph’s College New York) shed light on British efforts at the Paris Peace Conference, rooted in the blockade experience, to establish a multilateral sanctions regime through the League of Nations. The former blockade minister and British delegate at Paris, Lord Robert Cecil, considered the blockade a great success and believed that similarly organized international sanctions could guarantee peace in the future. However, these hopes were soon dashed and relatively little use was made of the League of Nations instruments for international sanctions. HEATHER JONES (University College London) expanded the geographical focus of the conference by drawing attention to the Mediterranean blockade in the First World War. Unlike the blockade in the Atlantic, the blockade in the Mediterranean was able to operate close to the shoreline and was often explicitly aimed at civilian populations. Still, subsequent starvation in the Mount Lebanon region, for example, failed to generate the broad moral condemnation that would develop, for example, in response to the aerial bombing of German cities during the Second World War. Jones thus laid bare the racial and cultural hierarchies that underpinned humanitarian opposition to blockade and as well as the imperial uses of the blockade in the Mediterranean.

The fourth panel “From the First to the Second World War”, focused specifically on raw materials. ALEXANDER DONGES (Universität Mannheim) took as a case study the German iron and steel industry between 1919 and 1945. The blockade of the First World War and the associated disruptions had exposed the vulnerability and import dependency of the German iron and steel industry, prompting significant German counter-strategies (imports from Sweden, creation of strategic reserves, substitution and, to a minor extent, mining of domestic ores), in the 1930s. Owing to these strategies, iron ore as well as the base metals for steel production did not become a major bottleneck during World War II. SIMON RENNER (NTNU Trondheim) drew attention to private businesses as actors in blockade preparation and implementation. Renner demonstrated how the Canadian International Nickel Company (INCO), a company that dominated the international nickel market in the era of the two wars, ended up serving German interests rather than British war preparations in the 1930s. INCO became Germany’s main supplier of unrefined nickel in the 1930s, thereby thwarting British plans to create a German nickel shortage in a future blockade. To prevent state interference, INCO influenced the public debate on a nickel embargo against Germany in the 1930s, with questionable and misleading claims. BASTIAN LINNEWEH (Universität Göttingen) talked about control of the rubber value chain in the era of two blockades. While the Great War had disrupted the global value chain of rubber, the interwar period saw various attempts to control the rubber market by the three major rubber-consuming countries: Britain, the United States and Germany. With the International Rubber Agreement of 1934, the rubber market was controlled on a global level and coordinated producers and consumers in various countries, including Britain and the United States. Nazi Germany adopted a different strategy and highly subsidized the production of BUNA, a synthetic alternative, thereby establishing an alternative value chain.

Panel 5, “From the First to Second World War, Part II”, was introduced by JONAS SCHERNER (Trondheim) who quantified the effect of the blockades on strategic raw materials and showed how German lessons from the First World War influenced preparations for the Second World War. Scherner concluded that the First Blockade led initially to a massive decline in raw material imports, but was partly overcome by German substitution and conservation measures. The Nazi regime learned distinct lessons from this experience and, through investing in R&D of substitutes and substitution industries, entered the Second World War far better prepared. However, this came at a considerable price (not least in labour costs). Indirectly, therefore, the blockade was important for the outcome of the war. CLOTILDE DRUELLE (Université de Limoges) gave insights into the French experience of the First Blockade and its influence in interwar France. She discussed various facets of the first blockade, from preemptive purchasing to trade prohibitions, economic intelligence, and financial controls. Although the blockade experience in interwar France was not forgotten or lost, it was not put to good use. The Blockade Ministry was dissolved in December 1918 and the blockade experience was not made fruitful. Discussions about human suffering and deaths caused by the blockade were also neglected. The knowledge about the First Blockade seems to have been hardly used for the next blockade either. Exploring the fierce debate about the creation and publication of the official British history of the blockade by Archibald Colquhoun Bell, published in 1937, MATTHEW SELIGMANN (Brunel University London) identified two competing narratives that characterized the interwar blockade discussion. Both believed that a blockade can in principle be successful. The first view, promoted by the Foreign Office, saw the implementation of the blockade as a full success, while the other, shared by certain naval officers and the right-wing press, saw weakness in the execution of the blockade, particularly in dealing with neutrals. With his presentation, Seligmann revealed the diversity of the discussion about the efficacy of the blockade inside government and the public sphere. The narrative of a successful blockade of World War I also played a role in the paper by ELISABETH PILLER (Universität Freiburg). She explored two instances of trans-blockade relief (in Belgium after 1914 and in Greece after 1941) and their interconnection. As she argued, blockade and the relief of Belgium after 1914 produced two very different lessons: a renewed emphasis on military necessity among the British blockaders and the German occupiers alike, and a new sense of potential for humanitarian actors. These lessons undercut relief operations during the Second World War (with the exception of Greece), but at the same time laid the foundation for modern food aid organizations after 1945.

The final panel focused on “Blockade, the Second World War and Beyond”. ANTÓNIO DUARTE (Portuguese Military Academy Lisbon) extended Nunes’ analysis of Portuguese strategy, focusing on the Second World War. As a neutral, autocratic state, Portugal again stood between belligerents, fearing a British maritime blockade as well as a German air and submarine blockade. Traditionally allied with England, Portugal maintained economic ties with Germany, notably supplying tungsten to Germany until 1944. Duarte showed that Portugal was not just a passive victim, caught between two enemy blocs, but an active agent with the capacity to negotiate from a position of strength. SHELDON GARON (Princeton University) moved the debate to the Pacific by discussing the transnational lessons of the First Blockade in Japan. Like Britain and Germany, Japan, too, was convinced that blockade, especially its effect on civilians, had helped the Allies win the First World War. At the same time, it assumed that proper countermeasures would make it possible to cope with the blockade. Consequently, Japanese strategies in the 1920s and 1930s aimed to increase food production, teach the Japanese how to rationalize food supply and promote imperial self-sufficiency in food. In 1945, however, the blockade and bombing raids associated with US “Operation Starvation” eventually led to serious food shortages. According to Garon, hunger was one factor that ended the war in the Pacific. MARK BAILEY (UNSW ADFA Canberra), too, focused on the Pacific, albeit from the perspective of current war planners. Bailey emphasized the utility of historical experiences of blockade to current war planning and drew parallels between pre-World War II plans against Imperial Japan and a possible blockade of China today. Bailey saw China as particularly vulnerable to blockade due to its import dependencies and belief in its own infallibility. A blockade might put pressure on China and thwart its plans for regional hegemony. Subsequently, conference participants discussed how the blockade experiences of the first half of the 20th century can shape today’s strategic considerations of a blockade against any other nation and if history in general can or should be an instrumental scholarship.

In a final contribution ALAN KRAMER (Dublin) demonstrated how the conference extended the perspective on the economic, social and cultural effects of blockade on various regions. He drew attention to several possibilities of how to define blockades, and how the understanding differed between countries and changed during the last century. He suggested that the concept of 'slow violence' can be fruitful in understanding intentions and interpretations of food blockades. Further research areas were identified in the quantification of economic effects, the repercussions on peripheries, transnational aspects, learning processes, and continuities from the first to the second blockade.

Conference overview:

Jonas Scherner (Trondheim)/Elisabeth Piller (Freiburg): Welcome

Alan Kramer (Dublin): Blockade in War & Peace: A Research Agenda

Hew Strachan (St Andrews): Grand Strategy and Blockade, 1914-1945

Panel 1: Britain and the Blockade in the Era of the First World War
Chair: Alan Kramer (Dublin)

Gabriela Frei (Munich): Blockade by Other Means or How to Deal with Neutrals? From the Boer War to the First World War

Avram Lytton (Calgary): Blockade: From the Maritime to the Continental

Panel 2: Global Blockade and the First World War, Part I
Chair: Oliver Janz (Berlin)

Samuël Kruizinga (Amsterdam): Spain, the Netherlands and the Relief of Belgium, 1917-1918

Teresa Nunes (Lisbon): Portugal and the Great War Blockade: From Neutrality to Belligerence

Panel 3: Global Blockade and the First World War, Part II
Chair: Jonas Scherner (Trondheim)

Marcel Boldorf (Lyon): The Legend of "Aushungerung." Germany under the Allied Blockade in World War I

Phillip Dehne (New York): After the Great War: Economic Warfare and the Promise of Peace in Paris 1919

Heather Jones (London): The Mediterranean blockade in the First World War

Panel 4: From the First to the Second World War, Part I (Strategic Raw Materials)
Chair: Madeleine Dungy (Trondheim)

Alexander Donges (Mannheim): Strategic War Planning in the German Iron and Steel Industry, 1919-1945

Simon Renner (Trondheim): Learning from the Blockade: British Plans for Economic Pressure on Germany in the late 1930s

Bastian Linneweh (Göttingen): Commodities of Global Conflict: Rubber Between the Blockades

Panel 5: From the First to Second World War, Part II
Chair: Hans Otto Frøland (Trondheim)

Jonas Scherner (Trondheim): Germany, Blockade and Strategic Raw Materials in the Era of the Two World Wars

Clotilde Druelle (Limoges): The Legacy of WWI Blockade in France during Interwar Period

Matthew Seligmann (London): Competing Narratives on Economic Warfare - The Unlikely Origin of Archibald Bell's Unwanted “History of the Blockade of Germany”

Elisabeth Piller (Freiburg): Negotiating Access. Blockade, the Two World Wars and the Making of Humanitarian Diplomacy

Panel 6: Blockade, the Second World War and Beyond
Chair: Elisabeth Piller

António Duarte (Lisbon): Portuguese Neutrality and the British Blockade during the Second World War

Sheldon Garon (Princeton): Blockade as Transnational Strategy: The Perspective from Japan

Mark Bailey (Canberra): Historical Blockade and Current Defence Planning - A View from the Pacific

Research Agenda and Closing Discussion

Alan Kramer (Dublin): Blockade in War and Peace: A Research Agenda

Closing Discussion: The Blockade in the Era of the Two World Wars