Expanded public subsidies for child care and prekindergarten command solid bipartisan support. According to recent polling, two-thirds of Republicans and nearly nine out of 10 Democrats would like to see Congress increase federal investment in early education. At the state level, public investment and student enrollment in prekindergarten increased at a faster rate in single-party-control Republican states than it did in Democratic states during the first half of the last decade. The child-care industry has been deeply affected by the coronavirus pandemic and attendant lockdowns. A report from the National Women's Law Center estimated that about one in five child-care workers lost their jobs between February and July 2020. Even before the pandemic, progressive politicians--including many of the Democratic presidential candidates--were calling for unprecedented expansions to federal investment in early education. This issue brief analyzes the research on early education. First, it presents and contextualizes the arguments made by early-education advocates and the research used to support those arguments. Then it reviews other studies that are frequently elided or ignored but that are more relevant to contemporary policy debates. These studies present a consistent pattern: while early education "can" be a profound boon for deeply disadvantaged students, it can also set disadvantaged students further back and potentially do lasting harm to students born into middle-class families.