A counterfactual of what might have happened if Churchill rather than Chamberlain had become chancellor and then prime minister is used to compare the two men. The evidence suggests foreign policy would have differed little before 1938. Like Chamberlain, Churchill would have prioritised the German threat over the Japanese, and would have tried to gain Italian support. Nor would he have used force to reverse Hitler’s occupation of the Rhineland or the Anschluss. On the other hand, Churchill’s approach to Czechoslovakia was fundamentally different from Chamberlain’s, being based on collective security rather than bilateral negotiations with Hitler. It is uncertain, however, whether an effective alliance could have been constructed to deter Germany. Churchill would have rearmed more rapidly than Chamberlain, being more willing to take risks with the economy, but both men prioritised the air force over the army, and for technical reasons British air power was not formidable in 1938. The question of whether it would have been better nevertheless to fight in 1938 rather than 1939 cannot be answered with certainty. Chamberlain’s personal diplomacy undoubtedly had serious shortcomings, but there is room for disagreement on moral issues associated with the Churchillian alternative, including the sacrifice of Ethiopia; the use of war as an instrument of foreign policy, particularly when public opinion was not united; and the risk of allowing Stalin to decide whether there should be peace or war.