Another Liberal leader bites the dust.

South Australia’s Martin Hamilton-Smith this morning announced his resignation, two days after winning a leadership ballot he called himself by just one vote — a position he correctly assessed as being untenable.

The parliamentary Liberal Party will meet on Wednesday to elect a new leader, with the novelty that the two leading contenders — present deputy (since Saturday) Isobel Redmond and former deputy and challenger Vickie Chapman — are both women.

South Australia is at the tail end of the state political cycle, with the Rann Labor government only on its second term, so its Liberal Party is the worst placed of the lot. Whoever wins on Wednesday will be its fourth leader in as many years, and face an impossible task in overhauling Labor’s huge majority: the latest polls show the opposition struggling to make up any ground.

There’s undeniably a relationship between leadership instability and poor performance, but no-one is sure which way causation runs. Although South Australia is still in the doldrums, most of the other state Liberal Parties are looking more stable on the leadership front.

A little over two years ago I drew attention to the fact that state Liberal parties between them had “changed leaders 20 times without winning an election.” At that point, the longest serving Liberal leader had been there just over a year.

Since then, however, Ted Baillieu in Victoria and Will Hodgman in Tasmania have racked up three years on the job; Barry O’Farrell in New South Wales has made it to two; and Western Australia’s Colin Barnett, although he became leader less than a year ago, has actually won an election — something none of the others have managed. Only Queensland, where the Liberal Party was subject to a hostile takeover, still shares South Australia’s instability.

None of the states have tried a female leader since NSW’s Kerry Chikarovski was deposed in 2002, so maybe that will help the South Australians to become more competitive. But if the experience of other states is any guide, what they most need is time: time for the Labor government to become stale, lose touch and be discredited.

When that happens, voters will eventually turn to the opposition — regardless of what leadership follies they’ve been up to in the meantime.