In this speech to Parliament, Churchill shared his opinion on England about following a policy of appeasement. I have always held the view that keeping peace depends on holding back the aggressor. After Hitler's seizure of Austria in March, I appealed to the government. I asked that Britain, together with France and other powers, guarantee the security of Czechoslovakia. If that course had been followed, events would not have fallen into this disastrous state. . . . in time, Czechoslovakia will be swallowed by the Nazi regime. . . . I think of all the opportunities to stop the growth of Nazi power which have been thrown away. The responsibility must rest with those who have control of our political affairs. They neither prevented Germany from rearming, nor did they rearm us in time. They weakened the League of Nations. . . . Thus they left us in the hour of trial without a strong national defense or system of international security. Source: Winston Churchill, 1938. critical idea for tis source

The critical idea from this source is that Churchill believed that the policy of appeasement followed by the British government in dealing with Hitler and Nazi Germany was a disastrous mistake. He argued that if Britain, together with France and other powers, had guaranteed the security of Czechoslovakia after Hitler's seizure of Austria, it could have prevented the further growth of Nazi power. He also criticized the British government for not preventing Germany's rearmament, failing to adequately strengthen the League of Nations, and leaving Britain without a strong national defense or system of international security. Churchill placed the responsibility for these failures on those who had control of the country's political affairs.