This book intends to analyze Reinhold Niebuhr's understanding of the state in his Christian Realism. Although his overall notion was thoroughly analyzed in different disciplines and respects, this specific focus can be diagnosed as a lacuna. The task of this book is to develop a hypothesis in terms of under what political, social, organizational or intellectual context Niebuhr made use of what definition of the state. When did he support the extension of state power (e. g. in war times, during economic crisis) and when did he criticize tendencies toward autocratic structures inside Western style democracies?