 Britain's Statute of Westminster 1931 formally ended most of the constitutional links between Australia and the UK. Australia adopted it in 1942, but it was backdated to 1939 to confirm the validity of legislation passed by the Australian Parliament during World War II. The shock of the United Kingdom's defeat in Asia in 1942 and the threat of Japanese invasion caused Australia to turn to the United States as a new ally and protector. Since 1951, Australia has been a formal military ally of the US, under the ANZUS treaty. After World War II Australia encouraged immigration from Europe. Since the 1970s and following the abolition of the White Australia policy, immigration from Asia and elsewhere was also promoted. As a result, Australia's demography, culture, and self-image were transformed. The final constitutional ties between Australia and the UK were severed with the passing of the Australia Act 1986, ending any British role in the government of the Australian States, and closing the option of judicial appeals to the Privy Council in London. In a 1999 referendum, 55 % of voters and a majority in every state rejected a proposal to become a republic with a president appointed by a two-thirds vote in both Houses of the Australian Parliament. Since the election of the Whitlam Government in 1972, there has been an increasing focus in foreign policy on ties with other Pacific Rim nations, while maintaining close ties with Australia's traditional allies and trading partners.
