Assess how the Emancipation Proclamation expanded ideas of freedom and liberty, looking at the antislavery debate that led to the proclamation, the influences on Lincoln's decision, and the provisions of the document. In this interactive lesson from WGBH, students develop a written argument in response to the question "In what ways did the Emancipation Proclamation expand ideas of freedom and liberty in America?" They gather evidence from videos featuring historian Ben Weber and from primary source documents, images, and artifacts.