Ted Baillieu’s good news month continued on Saturday, with a 12.3% swing to the Opposition in the Altona by-election, forcing the ALP to preferences for the first time since the seat was created.

The same swing uniformly repeated at a general election would deliver the coalition 30 seats, giving it a crushing 38-seat majority over the Labor/Greens combination.

That certainly won’t happen. But it does make the 5% or 6% swing that the coalition needs to win government in Victoria look a lot more manageable.

As has become common, both sides were playing the expectations game beforehand; Labor forecasting a big swing, the Liberals claiming that it would be difficult to get much swing at all. More neutral observers had been expecting something in the high single figures. The result, while not quite in the league of legendary by-election swings from Bass (1975, 13.8%) to Cabramatta (2008, 22%), was big enough to give Labor plenty of cause for concern.

Local comparisons are difficult because by-elections have been thin on the ground in Victoria in recent times. Neighboring Kororoit recorded a swing of only 4.1% in 2008, but that was complicated by the presence of a strong independent who almost outvoted the Liberal. The previous year, the Liberals refused to contest by-elections in Albert Park and Williamstown; taking the Greens as a proxy, they swung 2.6% and 10.1% respectively.

The Greens, incidentally, will be disappointed by Saturday’s result: their vote improved by 2%, to 10.4%, hurt by the increased number of candidates. Baillieu probably won’t be too upset about that; he wants the Greens to be strong enough to distract Labor in its inner-city heartland, but he has no interest in a large-scale protest vote that might seriously threaten the two-party system.

On the evidence of Altona, voter dissatisfaction with the choices they are offered is rather less than pundits would have us believe. None of the independents managed more than 2%, and despite the very short campaign, turnout was a respectable 84.7% (presumably with some postals still to come). The informal vote of 4.8% was actually down on the 2006 figure.

The swing was greatest (14.3%) in the rapidly developing suburbs of Point Cook and Seabrook, but the disparities were relatively small.

Altona proper, at the gentrifying eastern end of the electorate, swung 13.4%, and the safer Labor areas of Hoppers Crossing and Laverton/Altona Meadows 10.4%.

The Altona result, coming on top of a good opinion poll and poor publicity for the Government, presents Baillieu with a real opportunity to change the political narrative and present November’s election as challenging but winnable. In order to get much-needed oxygen for the Opposition, his primary task is to convince voters and the media that a swing is on and that the election is not a foregone conclusion.

Altona certainly makes that task easier.

It also makes Baillieu’s internal position, which was looking a bit shaky last year, much safer. Part of Labor’s spin on the result has been that they’re happy to keep Baillieu in his job, but this sounds like wishful thinking. While Baillieu certainly has his problems, there is no alternative remotely as credible on the Opposition front bench, and the novelty of leadership stability on the Liberal side should do them more good than harm.