The 1978 New South Wales state election was held on 7 October 1978 to elect all 99 members of the New South Wales Legislative Assembly. The Labor Party Government was returned for a second term, defeating the Opposition Liberal/National coalition in a landslide victory under leader Neville Wran. The election is popularly known as the "Wranslide".
It is notable for being so successful for the Labor Party that it tallied 57 percent of the primary vote, the largest primary vote for any party in over a century. Having gone into the election with a razor-thin majority of one seat, Labor scored a 13-seat swing, giving it a strong majority of 63 seats. Labor even managed to defeat the Leader of the Opposition, Peter Coleman, in his own electorate. The seats of many other prominent Shadow Ministers fell to Labor as well. Labor also won many seats in areas long reckoned as Coalition heartland. Among them were four seats that Labor had never won before this election--Willoughby (contested for the Liberal Party by Nick Greiner who later became Premier), Manly, Wakehurst and Cronulla. It also came within striking distance of taking several more. For instance, it pared down the margin in Pittwater, the seat of former premier Bob Askin, to only 1.4 percent.
The state's first elections to the New South Wales Legislative Council, the state parliament's upper house, were held simultaneously. Voters had approved a referendum to introduce a directly elected council in June of that year. Starting with this election, Single transferable voting (STV) was used to fill the Council seats up for election. The election of 15 members in a single contest was the largest District Magnitude seen in a STV election since the 1925 Ireland Senate election.https://www.tandfonline.com/doi/abs/10.1080/07907180500359327 It would be surpassed, again by NSW in 1995 when it began to elect 21 in a single contest.
The election was also the first in the state to be contested by the Australian Democrats.
Labor continued to campaign heavily on the strengths of Wran himself, with the slogan "Wran's our man".
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This election was held using STV for at-large election of members of Legislative Council.
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The final 2 party preferred result was 60.7% for Labor and 39.3% for the Coalition, making it one of the biggest landslide victories in New South Wales's electoral history. In 2PP terms it was a 9.1% swing to Labor from the Coalition. This was beaten by the Coalition's result of 64.2% and 35.8% for Labor in the 2011 election. However, Labor's record primary vote of 57.7 percent still stands today.