Isaacs covers south-eastern bayside Melbourne from Mordialloc south to Carrum, from which it extends inland as far as Western Port Highway to encompass Keysborough in the north and Carrum Downs in the south. The bayside suburbs are naturally marginal and shifted decisively to the Liberals at the state election in November 2010, whereas the centres further inland are strong for Labor.

Population growth, aided by development in and around Keysborough, has caused the electorate to lose territory in the latest redistribution, which transfers around 7500 voters in Springvale South and another 3500 in Cheltenham to Hotham. Labor’s strength in the former area is such that their margin has been shaved from 11% to 10.4%.

Isaacs was effectively created in 1969, and redistributions have made a strong mark on the seat’s electoral history — the presence or absence of Beaumaris at the northern coastal end being the decisive factor in the Liberals’ competitiveness. With Beaumaris in the electorate from 1969 to 1977, Labor’s only win was in 1974, when it provided a crucial gain for a beleaguered Whitlam government. David Charles gained the seat for Labor in 1980, and retained it until retirement in 1990 despite the return of Beaumaris in 1984.

Isaacs then became one of nine Victorian gains for the Liberals with Rod Atkinson’s win at the 1990 election. Atkinson held the seat for two terms before the electorate traded Beaumaris for southern bayside Chelsea and semi-rural Cranbourne, allowing Greg Wilton to win the seat for Labor against the trend of the 1996 election.

Wilton first survived an adverse 2.3% swing in 1996, having inherited a post-redistribution margin of 3.9%, and added a further 4.8% to his margin in 1998. His career ended in tragic circumstances in 2000 when he committed suicide amid widely publicised domestic troubles.

Wilton’s replacement, Ann Corcoran, lost preselection at the 2007 election to Mark Dreyfus, a prominent barrister and Queen’s Counsel who is now Attorney-General.

The Liberal candidate at the coming election is Garry Spencer, who obtained the rank of lieutenant-colonel in a 20-year career with the Australian Defence Force before working as a management consultant and engineering lecturer.