Australian Labor Party
The Australian Labor Party (ALP) is Australia's oldest continuous political party. The ALP was formed in 1891. The ALP has a strong connection to the trade union movement.
During the 1950s communist scare in Australia, the ALP expelled many anti-communist Catholic members. The anti-communist Catholic members became suspicious of communist influence in the trade union movement and groups were formed to take control of the unions. The groupers went on to form the anti-communist, Catholic aligned, Democratic Labor Party (DLP). The DLP became largely irrelevant after the election of a Federal ALP majority under Gough Whitlam in 1972.
Famous ALP prime ministers have included the war time John Curtin, 1970s Gough Whitlam and Bob Hawke. Although it has espoused socialist ideals in the past, the ALP has never introduced socialism to Australia. In recent decades, the ALP has remodelled itself in terms of its ideological vision to combat political pressure from outside sources.
An overwhelming majority of ALP MP's do not support same-sex marriage at the federal level. In 2004 an act titled The 'Marriage Amendment Act 2004' was introduced into the Australian House of Representatives which stated that marriage means the union of a man and a woman to the exclusion of all others, voluntarily entered into for life and that a union solemnised in a foreign country between:
(a) a man and another man; or
(b) a woman and another woman;
must not be recognised as a marriage in Australia. . It was passed by a majority of MP's in both chambers of parliament and in the Australian Senate only 6 Senators rejected the Bill compared to 38 who supported it. 
Julia Gillard is the current leader of the ALP, having taken over from Kevin Rudd on 24 June 2010 following a leadership coup. Ms Gillard subsequently became the first female Prime Minister of Australia.