New Zealand Labour centre-left politician, prime minister 1983-89. A skilled parliamentary debater, he became Labour's deputy leader in 1979, and in 1983 replaced Wallace Rowling as party leader. Taking advantage of economic difficulties and a changing public mood, Lange led Labour to a decisive win in the 1984 general election, replacing Robert Muldoon of the National Party as prime minister. The centre-piece of his policy programme was non-nuclear military policy. This was put into effect, despite criticism from the USA, becoming law in 1987. It prevented US nuclear-armed or nuclear-powered ships visiting New Zealand's ports and resulted in the USA suspending its defence obligations to New Zealand under the ANZUS treaty. Lange's government also introduced a free-market economic policy, which was a significant and controversial departure for Labour, and improved Maori rights and the position of women. His government was re-elected in 1987, but in August 1989 Lange unexpectedly resigned, as a result of health problems but also pressure being exerted by supporters of the right-wing former finance minister, Roger Douglas. Lange, who had become a critic of Douglas' liberalizing policies, had dismissed Douglas in 1988. Lange was replaced as prime minister by Geoffrey Palmer and served under him as attorney general until 1990.