Prohibits the United States from conducting explosive nuclear tests after enactment except in two narrow cases: if a foreign state conducts an explosive nuclear test first, or if a defined "technical need" requires a test. Before any permitted test, the President must give Congress at least 180 days' written notice with specified information and may only proceed if Congress enacts a joint resolution approving the test under expedited procedures set by the law.

The law amends existing authority to add detailed notice content, definitions (including "explosive nuclear testing" and "technical need"), and expedited introduction, referral, and floor procedures in both chambers. It also establishes special voting or procedural thresholds for Senate passage in some situations to implement the congressional approval requirement.