Understanding a legal document is more than a matter of reading and analyzing a text. Often it's helpful and, indeed, critical to know something about the context in which a particular event occurred and/or the document was written.
Both primary and secondary sources are used to create historical context.
Sources for primary resources: Try the History Research Guide. The home page offers lists of primary resources and library databases by geographic area.
Sample primary sources:
FOR HISTORICAL CONTEXT:
HeinOnline is a rich source of historical legal materials. In addition to large collections of law reviews, cases, Congressional materials, Presidential documents, and state legal resources, this database provides a number of specialized libraries of potential interest.
Some representative libraries include: the Pentagon Papers, Civil Rights and Social Justice, and Slavery in America and the World.
ProQuest Congressional provides access to a vast library of government publications.
Some representative collections include Presidential Papers, 1789 onwards, Congressional hearings from 1824, House and Senate reports, 1817 -
ProQuest History Vault - Primary resource materials.