This study explored expertise in searching for online information on a contentious historical and political question. Fact checkers, historians, and college students thought aloud while conducting online research on the question, "Did Margaret Sanger, the founder of Planned Parenthood, support euthanasia?" Analyses of screen recordings and think-aloud transcripts revealed that students clicked on sites near the top of search results and privileged evidence from primary sources. In contrast, historians and fact checkers used the search results as a source to help them understand the political context in which their query had landed them and to select reliable sources. Additionally, they searched for evidence from authoritative secondary sources. Implications for teaching online research and historical inquiry are explored.