This dissertation research explores whether and how local community residents employ uncivil language, such as hateful, aggressive, and vituperative words in social media platforms, focusing on residents of swing states during the 2018 midterm election period. As a theoretical framework, the logic of structural pluralism is employed to explain how local community members differently express their opinions in social media. Moral foundation dimensions are also used to explore how moral foundation spectrums are different based on local communication ecologies in local communities. This dissertation relies on computer-assisted content analyses of individuals’ social media comments collected during the pre- and post-election period. The data collection is administered retroactively, and both qualitative text analyses and quantitative path analyses are conducted in this dissertation research. The results show that those who access urban-located newspapers’ social media are more likely to employ uncivil language compared to people who visit suburban and rural-based newspapers’ social media accounts. Moreover, local community members tend to use uncivil words to respond to negative news topics such as crime news, law-related news, and news about local accidents, whereas those who consume news about weather and specific local regions are less likely to show incivility. Urban community members are more likely to use a wider range of moral foundation spectrums compared to suburban and rural community residents. Finally, urban residents who mention specific local counties located in the swing states are less likely to use uncivil language as they use words of the sanctity/degradation dimension. Mentioning specific locations in rural communities is also negatively associated with the use of uncivil language mediated by using words of the care/harm dimension. Based on the findings of the dissertation research, I elaborate on why swing states matter, how social media advance the logic of structural pluralism, how moral foundations are associated with cultural socialization, and why social media literacy matters.