What evidence is there in this document that the policy was a good idea?

his speech, he talked about a third alternative, he said if only British government were able to form alliances among countries against Germany and if they are able to strengthen air force and British Army, only then they could have prevented Germany from taking Sudetenland. He believed that Germany will continue to expand its territories eyeing in Western Europe and British territories are not exempted.  

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social contract theory, nearly as old as philosophy itself, is the view that persons' moral and/or political obligations are dependent upon a contract or agreement among them to form the society in which they live