Indiana University-Purdue University Indianapolis (IUPUI) / What do Americans think about the United Nations? Social scientists have put forward an array of viewpoints on the subject, focusing on such things as partisan differences in the attitudes of Americans towards the work of the UN to public skepticism of the organization’s objectives and effectiveness. I argue, in this thesis, that public opinion is a causal factor because of its potential to influence political outcomes. For example, public opinion can influence the effectiveness of the UN’s work in three main ways: 1) It can serve as an instrument for establishing the credibility of the international body’s work and/ or in discrediting the system as a whole; 2) it can serve as a link between the US and the UN in encouraging support for the United Nations in one of its most important members; and 3) Public opinion can stress the importance of a particular issue and pressure influential actors to take action. I choose to focus solely on the United States in this thesis despite the UN’s 192 other member states for the reason that overwhelmingly negative assessments have been offered of the organization since the Iraq War. The research depicting this idea points to a decline in American popular support for the UN in the past decade. By investigating six different hypotheses which seek to explain this possible decline, I conclude that American public support for the international body after the Iraq war has declined and can best be explained by hypothesis 3 on inadequate coverage of UN matters in the media and hypothesis 5 on the thought that the UN is “ineffective;” although this presumed decline is not steady due to opinion level variations in the recent decade.