What law did Congress pass first?
On June 1, 1789, the First Congress passed this law—the nation’s first. It required all members of Federal, state, and local governments to “solemnly swear or affirm to support the Constitution of the United States” before assuming their duties. This legal requirement has lasted more than 200 years. Today, no Government employee may start work without taking an oath. Text adapted from “The First Act of Congress” in the November/December 2004 National Council for the Social Studies (NCSS) publication Social Education.
National Archives, General Records of the U.S. Government