Answer: A change in government
On the back of this 1972 campaign, Gough Whitlam and his Australian Labor Party (ALP) swept into power, with Whitlam becoming Australia's 21st Prime Minister. Beyond taking Gough to the Lodge, what made this campaign so spectacular was that, in Australian political circles, there had been nothing like it before. After this, the way political parties in this country would campaign changed forever.
Back to this advert, McCallum, who was riding the crest of a wave with the success of her debut solo single, "Superman" (1972), delivered the song with the passion of a true devotee. But she wasn't alone in the song, with its chorus enhanced by a large group of, what was at the time, Australian entertainment royalty. Amongst these were the likes of Jack Thompson, Jackie Weaver, Graham Kennedy and Bert Newton. To put this into context, "It's Time" would do for the ALP what "We Are the World" did to draw attention to the plight of starving Africans in 1985.