Which action by the United States led to the creation of ballistic missile defense (BMD)?

• A. The United States withdrew from the ABM Treaty and eliminated the distinction between NMD and TMD.
• B. The United States established a space-based laser intercept system.
• C. The United States canceled all missile defense programs.
• D. The United States joined a new ABM treaty with Russia.

Answer: (A)

The central idea is how international treaties influence defense capabilities. The ABM Treaty of 1972 capped anti-ballistic missile defenses and kept a clear line between national and theater defenses to maintain strategic stability. When the United States withdrew from the ABM Treaty, those legal and strategic limits were removed. That change allowed building a broader ballistic missile defense that could protect the United States as a whole and integrate national and theater defense efforts, effectively eliminating the old distinction between NMD and TMD. The other options would not have driven the creation of BMD: canceling programs would halt it; joining a new ABM treaty would reimpose constraints; a space-based laser system describes a technology path, not the policy move that enabled BMD.