However, state ALP secretary Reggie Martin has vowed “the fight has not ended”, pledging to “lobby the State Government to make changes to the electoral law which would enshrine the importance of ‘one vote, one value’”.

Labor’s Supreme Court appeal was sunk by a unanimous decision of a full bench of five judges earlier this month, paving the way for the biggest shake-up of the electoral map since the contentious ‘fairness clause’ was introduced to the constitution act before the 1993 state election.

The clause is intended to ensure that, where practicable, the party with a statewide majority should be able to form government. But the Liberals have remained in Opposition despite garnering a two-party majority in three of the last four elections.

The Electoral Districts Boundaries Commission redistribution nominally handed the Liberals an extra four seats if they maintain their vote from the 2014 poll, but Labor argued the deliberate shifting of voters away from conservative regional electorates betrayed the principle – also enshrined in the act – of ‘one vote, one value’.

However, the Supreme Court dismissed the appeal, ruling that the commission is entitled to change the size of electorates provided they remain within the allowable 10 per cent “tolerance”.

Martin today wrote to party members and MPs, telling them: “While we respectfully disagree with the decision of the supreme court, we are pessimistic about our chances of success on further appeal.”

“We have spent the intervening time considering whether to appeal the decision to the High Court,” he wrote.

“After in-depth analysis by our legal team, and a second opinion from one of Australia’s leading High Court barristers, I have made the decision not to appeal.”

It’s understood the legal opinion held that even seeking leave for such an appeal risked being rejected by the High Court, given the highest court in SA had already ruled on a matter than is fundamentally a question of state law.

Martin said that he instead intends “to lobby the State Government to make changes to the electoral law which would enshrine the importance of one vote, one value”.

“We argued that there was an implication in the state constitution which confirmed the concept of one vote one value; however, the court disagreed, so we must now take the next step and ensure that the intent of the changes made by Dunstan in 1975 are enshrined in their importance,” he wrote.

“While we didn’t win the case, the fight for one vote, one value, has not ended.”

But further constitutional change seems a pipe dream for now, with the Liberals unlikely to support any such move.

Despite the fighting rhetoric, the defeat is a political blow for Labor, and potentially a financial one, with the Supreme Court still to rule as to whether the ALP should pay the Liberal Party’s legal costs.

It does however mean that the current round of preselections by both parties will not have to be aborted.

Congratulations to Nick McBride – preselected as the Liberal candidate for MacKillop at the 2018 state election. pic.twitter.com/yEYCCGEUjQ

— Steven Marshall (@marshall_steven) March 19, 2017

Labor last week confirmed Housing Choices state manager Julie Duncan for the newly-marginal northern suburbs seat of King.

https://twitter.com/saschameldrum/status/842888955162849282