The Australian Constitution gave the Commonwealth not a “treaty power” but a vague power over “external affairs,” the precise meaning of which was elusive for most of the twentieth century. From the 1930s, Labor judges and politicians such as H. V. Evatt saw its potential to extend Commonwealth power by legislating international agreements throughout Australia. The non-Labor parties rejected the idea of using the “external affairs” power to legislate in areas formerly the responsibility of the states but the federal Labor Party continued in the Evatt tradition. After significant uncertainties, the Whitlam government used the external affairs power to pass the Racial Discrimination Act 1975, the first significant human rights legislation in the country, which in turn had a profound effect on the law of the land in the country by making the second Mabo Case possible.