The First World War catalysed the birth of the American diplomatic history as an independent historical research field.Initially,it focused on significant events,such as war,peace and national security,mainly by relying on official archives.Since the 1980s,historians of the American diplomatic history paid attention to the experience of research methods of social and cultural history,and examined the influence of cultural factors on the diplomacy,including race,gender,and religion.Meanwhile,they also borrowed research methods from studies of international history,transnational history,and global history,not only emphasising on issues of war and peace,but also shifting their attention to the effects of issues relating to commerce,immigration and human rights on foreign relations.In the early 21st century,scholars fiercely debated on the direction of the American diplomatic history,focusing on whether to contribute to deepen international and transnational approaches or to adhere to the American national standards in diplomatic historiography.Many of them still emphasised the impact of domestic factors on the American foreign relations,advocating putting the state back at the centre of diplomatic history studies and paying close attention to traditional topics,such as war,diplomatic affairs,military power,and the ideological roots and decision-making circumstances of world leaders.In this sense,the'New Diplomatic History'has not replaced and is unlikely to replace traditional diplomatic history.The so-called paradigm revolution did not occur in the field of the American diplomatic history.The historians of this field now face new challenges and issues,such as integrating more effectively with the academic field of international relations,the ascent of the'non-West'in international relations studies,and the lack of scholarly tomes with global influence.