Scholarship has now recognized the potentially detrimental effects of social media on political knowledge. At the same time, a separate but similar line of work has raised concerns that these platforms are the primary vector of political misinformation. Despite the renewed focus on misinformation studies, the question as to whether political knowledge and susceptibility to misinformation are related remains open. If they are indeed related, we still know little about the underlying cognitive mechanisms that drive political learning when people rely on social media for news. Based on a two-wave panel survey collected during the 2020 U.S. presidential election, we found that social media news use fosters the news-finds-me perception (particularly among those who feel overwhelmed with the volume of information available on social media). This, in turn, leads people to be both uninformed and misinformed about politics and current affairs. Implications for democracy are discussed.