The Sleepwalkers

The story in brief

Christopher Clark is an Australian historian, Regius Professor of History at Cambridge, whose previous books were on Prussia. The Sleepwalkers, published in 2012, two years before the centenary of the war, became a bestseller across Europe and especially in Germany.

The book begins not in Sarajevo but in Belgrade, in June 1903, when a group of Serbian army officers murdered King Alexander and Queen Draga and brought a new dynasty to power. Clark traces how that coup shaped Serbian politics, including the network of officers who later helped arm the young Bosnian Serbs who assassinated Archduke Franz Ferdinand in Sarajevo on 28 June 1914. He then examines each great power in turn: how decisions were made, who made them and what they feared. Only in the last part does he follow the July crisis day by day, from the assassination to the declarations of war at the start of August.

The decisions that made it

Austria-Hungary’s leaders decided, in the days after Sarajevo, that the assassination justified a military response against Serbia, which they saw as a growing threat to the survival of their multinational empire. They sought and received German assurances of support, the so-called blank cheque of early July. They then took weeks to prepare an ultimatum, delivered on 23 July, with terms designed to be very hard to accept. Serbia’s reply was conciliatory on most points but rejected one, and Austria-Hungary declared war on 28 July.

Germany’s leaders gave their support believing, or hoping, that the conflict would remain local, and that Russia would not intervene or, if it did, that it was better to fight sooner than later, before Russian military reforms were complete.

Russia’s leaders, with French encouragement, decided early in the crisis that they would not allow Serbia to be crushed. Clark gives weight to measures Russia took from 25 July, in a “period preparatory to war”, which began military preparations before general mobilisation and fed German fears that time was running out.

France’s president, Raymond Poincaré, visited St Petersburg in the critical days of late July, and Clark argues that France’s leaders reinforced Russia’s firmness rather than urging restraint.

Britain’s foreign secretary, Edward Grey, kept his options open, partly because the cabinet was divided, and only committed Britain fully after Germany invaded Belgium.

Clark shows each decision as a choice among alternatives, made by small groups under pressure, often with poor information about what the others intended.

What the book sees in them

Clark’s argument is that the war was a tragedy, not a crime. Responsibility was shared among the powers, and the question of war guilt, which dominated debate after 1919, obscures more than it reveals. His title captures the view. The men of 1914 were alert to every move their rivals made and yet failed to see what their own choices were bringing about, like sleepwalkers moving with open eyes toward a disaster they could not imagine.

He emphasises several features of the crisis. Decision-making in each capital was fragmented, with ministers, military chiefs and monarchs competing for influence, so that foreign governments could not tell whose voice was authoritative. Each power acted on worst-case assumptions about its rivals. The alliance system turned a regional crisis into a continental one. And leaders saw war as an instrument of policy, without imagining what an industrial war would mean.

The book also shows how plausible the choices seemed at the time. Clark avoids hindsight, the temptation to see the war as inevitable once one knows it happened. The site’s idea page Hindsight and the Illusion of Inevitability explores that temptation.

Since it was published

The book’s reception was strongest in Germany, where it was seen as challenging the view, associated with the historian Fritz Fischer since the 1960s, that Germany bore primary responsibility for the war. Some historians, including John Röhl, argued that Clark underplayed German responsibility and overstated Serbia’s role, while others welcomed its comparative approach. The debate has continued, and has sometimes been taken up in political arguments about Germany’s place in Europe, which Clark himself resisted. He was knighted in 2015 for services to Anglo-German relations.

The book has also been widely read by people who study strategic decision-making, because it shows in detail how a crisis can escalate when each side misreads the other. Commentators frequently invoke it in discussions of tensions between the United States and China, a comparison that Graham Allison’s Destined for War develops.

What it asks of someone deciding

The book asks who actually speaks for your organisation, and whether outsiders can tell. In 1914 foreign governments could not know which of several competing voices in another capital reflected policy. Organisations with unclear authority send mixed signals to partners and competitors alike.

It asks what you assume your rivals intend. Each power assumed the worst and acted to protect itself, and each defensive act looked offensive to the others. Escalation in markets and negotiations often follows the same pattern.

It asks whether you can imagine the consequences of the course you are on. The leaders of 1914 expected a short war. The capacity to picture what a decision might really bring, as distinct from what one hopes it will bring, is what they most lacked.