The main lessons from Saturday’s ACT election and NSW by-elections can be heard loud and clear from the news headlines, and could indeed have been ascertained even before the figures came in. After suffering the two worst by-election swings in NSW history in Ryde and Cabramatta, there is no coming back for the fourth-term Labor government. The ACT election further emphasised that Labor’s state and territory governments are marching in lock-step towards the wrong end of the electoral cycle. While Jon Stanhope is likely to continue in government with the support of the Greens, Labor’s vote was down a numbing 9.3 per cent to 37.6 per cent. There were also intimations over the weekend that South Australia’s government is becoming conscious of its mortality, with talk of Treasurer Kevin Foley plotting a move against Premier Mike Rann.

The ACT election provided further support for the other recurring theme of recent state and territory elections: the growing strength of the Greens. The party is certain to hold the balance of power for the first time after its vote went up 6.6 per cent to 15.8 per cent, securing a definite three seats out of 17 and perhaps even a fourth. While the Greens’ more excitable partisans might interpret this as the tide of history leading the party on to fortune, past experience suggests a more mundane explanation. After a few terms in office, Labor governments often find themselves facing disaffection among voters of an idealistic persuasion, resulting in loss of support to minor parties and independents. The hard-edged economic reforms of the 1980s produced a bonanza for independents when Labor lost office in NSW in 1988, and compelled the Hawke government to make its famous pitch for Greens and Democrats preferences as its primary vote sank in 1990.

Now that there’s a monopoly trader in the market for disaffected left-wing votes, the Greens are presenting Labor with a perfect storm at the next round of state elections. They thus stand poised to fulfil long-cherished but never quite realised ambitions for lower house seats. Since the threat to Labor is in their traditional inner-city strongholds, the victims could include some very senior figures. In NSW, the Greens need to gain only 3.2 per cent on Labor to claim the scalp of Education Minister Verity Firth in Balmain, which Dawn Fraser won as an independent the last time Labor lost office. On current form, that would seem to be an absolute certainty. Marrickville could also go if the fall in Labor’s vote approaches double figures, which would put Deputy Premier Carmel Tebbutt out of a job. While things aren’t looking quite so grim for Labor south of the border, it’s clear the Victorian party’s vote in 2010 will not reach the landslide proportions of 2002 and 2006. That means big trouble for another Education Minister in Bronwyn Pike, who needed a feverish last-week campaigning effort in 2006 to retain a 2.0 per cent margin in her seat of Melbourne. Also at risk are Housing and Local Government Minister Richard Wynne in Richmond (margin 3.6 per cent), along with back-benchers Carlo Carli (Brunswick, 4.6 per cent) and Fiona Richardson (Northcote, 8.5 per cent).

Then there’s the risk that the phenomenon might go federal, as suggested by the recent Newspoll showing Greens support at 13 per cent. Such figures would be viewed nervously by Finance Minister Lindsay Tanner, who last November watched a Greens candidate take second place for the first time at a general election in his seat of Melbourne. This continued a trend of ominously mounting Greens support in Melbourne going back three elections: 6.1 per cent in 1998, 15.7 per cent in 2001, 19.0 per cent in 2004, 22.8 per cent in 2007. Tanner’s primary vote of 49.5 per cent kept him out of danger, but this was achieved at the peak of Labor’s electoral cycle. It’s not hard to conceive a scenario where the Rudd government pursues votes in the electorally decisive outer suburbs at the expense of the values held dear in the inner-city, which could place Tanner in serious jeopardy.