The theoretical distinction between tactical and strategic air warfare was developed between the two world wars. Some leading theorists of strategic air warfare during this period were the Italian Giulio Douhet, the Trenchard school in the United Kingdom, and General Billy Mitchell in the United States. These theorists were highly influential, both on the military justification for an independent air force (such as the Royal Air Force) and in influencing political thoughts on a future war as exemplified by Stanley Baldwin's 1932 comment that the bomber will always get through.