In 1987, Lange's government passed the New Zealand Nuclear Free Zone, Disarmament, and Arms Control Act 1987. This Act effectively declared New Zealand a nuclear-free zone and banned all nuclear-capable ships from entering New Zealand waters. The United States regarded this legislation as a breach of treaty obligations under ANZUS and announced that it would suspend its treaty obligations to New Zealand until the re-admission of U.S. Navy ships to New Zealand ports, characterising New Zealand as "a friend, but not an ally".