In 1985, the nature of the ANZUS alliance changed significantly. Due to a current of anti-nuclear sentiment within New Zealand, tension had long been present between ANZUS members as the United States is a declared nuclear power. France, a naval power and a declared nuclear power, had been conducting nuclear tests on South Pacific Islands. Following the victory of the New Zealand Labour Party in election in 1984, Prime Minister David Lange barred nuclear-powered or nuclear-armed ships from using New Zealand ports or entering New Zealand waters. Reasons given were the dangers of nuclear weapons, continued French nuclear testing in the South Pacific, and opposition to US President Ronald Reagan's policy of aggressively confronting the Soviet Union.