Although democracies are generally unlikely to enter civil war (see this list of civil wars for a rough overview), the United States faces a particularly unusual situation at the moment. The current COVID-19 pandemic, social protests, effects of social media platform manipulation, and the presidential election all have the potential to disrupt social cohesion and garner negative attitudes toward the government. See this related question for a shorter timeframe: Will the USA enter a second civil war before July 2021?