50 signatures to be eligible to stand. An unsuccessful challenge to the 500 member requirement was heard by the High Court of Australia in 2004. Other Australian jurisdictions require political parties to have a minimum number of members. For example, New South Wales requires at least 750 members while the ACT and the Northern Territory require 100 members. There are deadlines for registration of a political party. Australia has a de facto two-party system, with the Australian Labor Party and the Coalition of the Liberal Party of Australia, National Party of Australia, the Liberal National Party and Country Liberal Party dominating Parliamentary elections. It is very difficult for other parties to win representation in the House, let alone form the government, though they may have a strong influence if they hold the "balance of power". However, minor parties and independent candidates have been elected to the Senate by virtue of its more favourable voting system. In recent decades, several parties besides the ALP and the Coalition have secured significant representation in the Senate, notably the DLP (1955–1974); the Australian Democrats (1977–2007); and the Australian Greens and its predecessors (1990–present). Independent and other individual senators have also exercised influence, e.g., Brian Harradine (1975–2005), Family First's Steve Fielding (2005–2011), and Nick Xenophon (2008–2017); and, variously from 1984, representatives of the Nuclear Disarmament Party and One Nation. Many voters use elections to reaffirm their party allegiance. Party affiliation has declined in recent decades. Voters who voted for the same party each election made up 72% of the electorate in 1967. This figure had declined to 45% by 2007. Minor parties have played a greater role in the politics of Australia since proportional representation was progressively introduced. Elections in Australia are seen by parties as a chance to develop and refine policies. Rather than a procedure where the best policies win the day, elections are contests where parties fight for power. Elections are not part of the process in which specific decisions on policy are made. Control of policy and platforms are wholly determined within the party. Candidate selection, in Australia typically called preselection, is a significant factor in the democratic process in Australia because the majority of voters base their decision at election time on the party rather than the candidate. In Australia the decision of who may be a candidate is decided by the party in any manner they choose. It can