Diefenbaker was repeatedly a candidate for the PC leadership. He gained that party position in 1956, on his third attempt. In 1957, he led the Tories to their first electoral victory in 27 years; a year later he called a snap election and spearheaded them to one of their greatest triumphs. Diefenbaker appointed the first female minister in Canadian history to his Cabinet, as well as the first aboriginal member of the Senate. During his six years as Prime Minister, his government obtained passage of the "Canadian Bill of Rights" and granted the vote to the First Nations and Inuit peoples. In foreign policy, his stance against apartheid helped secure the departure of South Africa from the Commonwealth of Nations, but his indecision on whether to accept Bomarc nuclear missiles from the United States led to his government's downfall. Diefenbaker is also remembered for his role in the 1959 cancellation of the Avro Arrow project.