This dissertation revisits the "rally-round-the-flag" (RRTF) phenomenon in which the popularity of U.S. presidents increases sharply after major war events and during security crises. Existing explanations often ignore the role of emotions in the formation of political attitudes, or include only negative emotions and overlook positive ones. Further, existing approaches lack a focus on the nationalist framing of the situation and the nationalist emotions of pride, confidence, and hope. Finally, previous approaches often miss the fact that the RRTF effect is co-produced through an interaction between official rhetoric and the perceptions and nationalist sentiment of the general population.

Chapter 1 proposes that the RRTF effect emerges when and if a major war or security crisis is widely perceived as an opportunity to enhance the prestige of the nation, thereby activating a popular nationalist sentiment. Under these circumstances, individuals experience positive emotions--pride, hope, and confidence--associated with their membership in the nation. These emotions facilitate a positive evaluation of military action, and therefore motivate individuals to support the president. Chapter 2 applies the qualitative comparative analysis technique to data on all major war and security crises in the United States from 1950 to 2006. The findings reveal that RRTF periods have emerged when the presidential rhetoric and the supporting historical circumstances have led the public to consider war events or security crises as opportunities to reclaim or enhance the prestige the nation has vis-à-vis other nations. The investigation did not support alternative arguments proposed in the literature. Chapter 3 analyzes survey data collected during the presidency of George W. Bush and shows that support for the president during two RRTF periods was motivated primarily by positive emotions about Bush's antiterrorism policy, and these emotions stemmed from national identification. Chapter 4 reports the results of a survey-based experiment. The findings demonstrate that participants who were exposed to official rhetoric that used nationalist language to justify military action against Iran reported higher levels of nationalist sentiment, pride, and confidence, and were more likely to support military action than participants who were either exposed to internationalist rhetoric or assigned to a control group.