The Constitution requires all government office-holders to take an oath to support that document, but it ... No one felt anything more was needed—until the Civil War. In 1862, Congress adopted the "Ironclad Test Oath." Civil servants and military officers had to swear loyalty to the Union and affirm no previous disloyalty.
Most research uses both primary and secondary sources. They complement each other to help you build a convincing argument. Primary sources are more credible as evidence, but secondary sources show how your work relates to existing research.
