"We don't have a community in America anymore": Theorizing how social media platforms mediate mutually destructive relationships between news, political discourse, and a sense of community Abstract: This study investigates users’ perspectives on the role that social media platforms play in weakening a sense of community—particularly in a highly polarized U.S. political environment. Analyzing data from eight focus group sessions, we present three thematic areas of findings: changes in the media economy, disruptions to a sense of community, and reactions to a lost sense of community. Putting these findings in conversation with prior work on media and community, we offer a theoretical model on how platforms mediate a series of anti-democratic interactions between political news, political discourse, and feelings of community and connectedness—interactions which ultimately have negative consequences, both online and offline. Participants expressed feelings of futility towards resolving this issue and exhibited nostalgia for a pre- or early- social media era, which we theorize as both evidence and consequence of discontent with our current platform society.