As Angela Lyne’s train slowly crosses France towards the Channel in the dying days of August 1939, she thinks of the way politics had been “tediously on every tongue” among the idle rich at Cannes. “The French and Italians whom she met had said war was impossible; they said it with assurance before the Russian pact, with double assurance after it. The English said there would be war, but not immediately. Only the Americans knew what was coming, and exactly when.”

What those Americans—in Evelyn Waugh’s novel Put Out More Flags, which appeared in 1942—had sensed was that Germany was flexing its muscles for an invasion of Poland. It came on September 1, and two days later Great Britain and France reluctantly but finally declared war on Germany. Few realized that Hitler had been on the point of launching his attack nearly a week earlier; when hostilities did begin, it followed a tense sequence of bluff and counterbluff, and in a way which shows that “nothing in history is inevitable,” as Richard Overy writes in his ingenious and enthralling book. 1939: Countdown to War is short but detailed, and it covers no more than the days from August 24 to September 3—but surely there have been few more extraordinary eleven-day periods in history.

Everyone concerned had vivid memories of another terrible war just over twenty years before. National leaders were desperate to avoid a repetition of that slaughter, with the exception of Hitler, who was determined to avenge and to re-write the outcome. What had happened in 1918 was indeed lamentable. Germany was defeated, but in a way that made it possible for Germans to believe that they had been cheated of victory; and a settlement had been drawn up, but in a manner that made it possible for Germans to believe that it was a monstrously unjust “slave treaty.” 

Both beliefs were false, but together they were poisonous. To complicate matters, many people, not least English and American liberals, originally sympathized with German grievances over the forcible separation of Austria from Germany and over the creation of a new Czech state that included more than three million unwilling Germans. Those supposed wrongs were disposed of in the course of 1938, leaving one more grievance in the form of Danzig, a German port on the Baltic that had been declared a “Free City” as a compromise by the Versailles settlement. 

Alas for liberal optimism. Germany was now ruled by a savagely persecuting tyrant who embodied racial hatred and assertive nationalism. Having bluffed his way to power in 1933, Hitler bluffed his way through the next six years, outwitting Neville Chamberlain at Munich as he had outwitted the German politicians who first thought they could make use of him. But in March 1939, Overy writes, “the battle lines of the war were laid.” When the rump “Czecho-Slovakia” fell apart and Hitler went in triumph to Prague, even poor Chamberlain realized that he had been deceived, and in reaction he gave the Poles a commitment he had denied the Czechs. At the same time Józef Beck, the Polish foreign minister, told his colleagues, “This is clear. We will fight.”

By then it was scarcely surprising that Hitler thought he could get what he wanted, and that the two Western powers would never honor their commitments; he believed that they would always give way in a final test of wills if war were the alternative. In fact, as Overy shows, the British and the French, and in particular Chamberlain, made it clear throughout the summer that they would support Poland if it was attacked. Having been pitifully mistaken when he thought that (in the prime minister’s own unhappy words) he could “do business” with Hitler, he now called him “the blackest devil he had ever met.” 

After weeks of border skirmishes, Hitler secretly ordered a mobilization as a prelude to an attack that he had planned for August 26. War did not break out that day, but only as a result of something that stunned the world: the Molotov-Ribbentrop Pact, which was announced on August 24. A generation of leftist intellectuals stood dumbfounded and discomposed, while others saw a terrible symmetry in this alliance of two diabolical powers, Soviet Socialist Russia and National Socialist Germany. In diplomatic terms, its outcome was unforeseen and unintended. It is easy now to think of the Pact as having brought war nearer, but over the next five days the leading players thought the opposite. Hitler believed that Anglo-Franco-Polish solidarity would collapse after the Pact, while London and Paris believed that their own renewed show of resolution would make Hitler back down.

By the end of the month, everyone knew what was coming, and not just those Americans on the Côte d’Azur. German troops crossed the Polish border on Friday, September 1. On Saturday, the House of Commons met in an emergency session, expecting to hear a declaration of war, and there ensued a few electrifying minutes. Chamberlain made a stilted little speech saying that the German aggression violated treaties, but then said no more before sitting down in dead silence. As one MP recorded, “Members sat as if turned to stone,” mortified with shame, until the Commons chamber heard the single most famous interjection in Parliamentary history. When Arthur Greenwood of Labour rose to reply, deputizing for C.R Attlee, the Leader of the Opposition, the veteran Tory Leo Amery shouted, “Speak for England!” At 11:15 the following morning, a Sunday “of unusual beauty, clear hot sun, dazzlingly white clouds,” as one writer recorded, the British people listened to Chamberlain’s sorrowful short radio speech saying that, in spite of all his efforts to maintain peace, the country was at war.

Who was responsible for the war in 1914 had been endlessly and acrimoniously debated, and so it would be again after the next war. To say that Hitler was the guilty man is in an obvious sense true, but does not address the proximate causes. When Overy says that “it was Poland’s intransigent refusal to make any concessions to its powerful German neighbour that made war almost certain,” he does not of course mean that the Poles started the war. (That would be reminiscent of the paradox-mongering young historian on the make in Alan Bennett’s The History Boys who makes his name by saying things like “The Japanese were caught napping at Pearl Harbor.”) Less than a year earlier, the Czechs had been abandoned and forced to capitulate. Having witnessed this—and shared the spoils of Munich—the Poles were now determined not to share the Czechs’ fate. Their determination brought another sort of disaster, although nothing at the date would likely have changed Hitler’s plans. 

Some readers may be surprised by Overy’s leniency to Chamberlain. Chamberlain tried to avoid war by conciliation or appeasement and then tried by the opposite course; his final decision for war “was certainly a courageous act,” and taken in excruciating circumstances. As Overy says, in words that resonate to this day, democratic leaders enjoyed none of the happy simplicity enjoyed by dictators in choosing war.

One country sat out events that August with distant detachment. President Franklin Roosevelt was his usual feline and inscrutable self, offering no commitments to any side, certainly not the British and the French. Even if he had wanted to enter the war, which he did not, he could not have taken his electorate with him: in one poll that appeared in August, 92 percent of Americans said they did not want their country to fight.  

But this was not just another war, and its outbreak was not a mere inning in the Great Game of nations. Little details remind us of the different moral character of the participants, which would become horribly clear in the next years. Later in the war the British excelled at deception, as Ben Macintyre has shown in his entertaining book Operation Mincemeat, about the way in which the corpse of a vagrant was dressed in British officer’s uniform and provided with secret documents—in fact phony misleading plans—before being left to wash ashore on to the coast of Spain. But at least the unfortunate who became “Major William Martin” had been found dead. When the Germans wanted to fabricate an “incursion” by the Polish army to which they could respond, they briskly selected six inmates from Sachsenhausen concentration camp, dressed them in Polish uniform, and then shot them, before leaving their bodies at the Hochlinden customs post that they had supposedly attacked. The German army had begun the war in the spirit in which it would fight it. 

Geoffrey Wheatcroft is the author of The Strange Death of Tory England and Yo, Blair!