What was Britain fighting for, then? To this question, the Chamberlain government did have a clear answer. Britain’s ultimate war aim was to induce a “change of heart” in Germany, which Britain would do by showing it, once and for all, that aggression does not pay. A German withdrawal from Poland and Czechoslovakia would provide evidence of this “change of heart,” but in and of itself it was insufficient. A withdrawal was a mechanical act; a change of heart, a spiritual one. The Chamberlain government was never able to clearly define what constituted an authentic change of heart. Still, the prime minister was confident if Germany had one, he would recognize it. Did Britain seek the military defeat of Germany? The Chamberlain government also had a clear answer to this question: only as a last resort. Until about March 1940, the prime minister remained confident that blockade and propaganda would produce victory, either by inducing a collapse of the German economy or by triggering a revolt of the German masses—or, perhaps, both.

During a meeting of the Allied Supreme War Council in December 1939, then premier Daladier made it clear to Chamberlain that vague British talk of punishing aggression was insufficient. It was “essential . . . to make it impossible for Germany to disturb the peace once more.” That was French for dismembering the German state. A few days later General Henry Pownall, a BEF staff officer, told Chamberlain that General Alphonse Georges, the deputy commander of the French Army, had warned that “if the British again stood in the way of what the French considered a fair solution, they would never forgive us.” In a January 1940 speech, the prime minister attempted to appease his French critics by blaming the German people as well as their leaders for the war. Chamberlain was careful to qualify the accusation, though. “To put it about that the Allies desire the annihilation [of Germany] is a fantastic and malicious invention. . . . On the other hand, [the] German people must realize that the responsibility for the prolongation of this war and of the suffering it might bring in the coming years is theirs, as well as the tyrants who stand over them.” To keep the French sweet, on occasion other cabinet ministers would make similarly bellicose pronouncements. In a November 1939 speech, Lord Halifax talked of “secur[ing] the defeat of Germany,” and in a February 1940 interview, Oliver Stanley, the secretary of state for war, told the Daily Telegraph, “I have only one war aim, to win the war.” By early March, with the British public confused about Britain’s war aims and the French government alarmed by them, Chamberlain was feeling the need to take bold action. Hence he decided to revisit an idea he had discussed with Daladier the previous December: Britain and France would pledge not to sign a separate peace agreement with Germany; such a pact would ease French suspicions about British resolve and provide an umbrella under which French and British differences over war aims could be hidden. Within weeks, the no-separate-peace pledge was placed on the agenda of the March 28 Allied Supreme Council meeting in London. But before addressing the pledge, Chamberlain intended to put Reynaud in his place.

On the evening of the twenty-seventh, the new French premier arrived in London amid a swirl of rumor and innuendo so dense it constituted its own weather system. It was said of Reynaud that he was overly dependent on his mistress, the Comtesse Hélène de Portes, that he had “the proclivities of a pocket Napoleon,” that he had a “small man’s arrogance,” that he was a “lightweight” and “high-strung,” and that he was less representative of the real France than his predecessor, the earthy Daladier.

The next morning, at the opening meeting of the Allied Supreme Council, Chamberlain set to work on the premier. One of the other guests, General Edmund Ironside, the chief of the Imperial General Staff, marveled at the prime minister’s skill. Chamberlain opened the meeting “with a ninety minute monologue on the general situation . . . [that] took all the thunder out of Reynaud and left him gasping with no electric power,” Ironside noted. “All the ‘projects’ that Reynaud had to bring forward, Chamberlain took away. It was masterly and very well done. Little Reynaud sat there with his head nodding in a sort of ‘tik,’ understanding it all, for he speaks English very well.” By the end of the meeting, Reynaud looked “for the entire world like a little marmoset.”

Reynaud, who knew a thing or two about political infighting himself, transcended the humiliation. He had brought along one good card—the fragile state of French public opinion—and, a gifted orator, he played the card with flair and drama. He told the Supreme Council that the French people were angry at being dragged into the war by the reckless British guarantee to Poland, angry at the pretense that eight underequipped British divisions in France (each with twelve thousand to fifteen thousand men) represented an effort du sange (effort of the blood); and he warned that his countrymen and -women were becoming increasingly susceptible to German claims that France was fighting Britain’s war for it. The speech tapped into a deep vein of British guilt. Seven months into the Great War, Britain had established twenty-nine divisions in France, all fully equipped.

Chamberlain, whose eagerness to do something “spectacular” had not previously included setting a date for doing it, now agreed to a schedule. On April 1, the Allies would issue a warning to the Norwegian and Swedish governments, and on the fifth the Allies would commence Operation Wilfred, the mining of Norwegian waters.