There’s a furious battle being fought over the Canning by-election, yet it’s not the campaign that voters are being subjected to through their letterboxes and TV screens.

This parallel campaign is more subtle and surreptitious. It’s a shadow campaign, using mostly off-the-record comments to the media, aimed at shaping our expectations of the Canning outcome and ultimately our perception of what it all means.

Labor is downplaying their chances of winning the seat, and will likely eschew any credit for the expected swing away from the Government by framing the result as a protest vote against the PM.

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Meanwhile, the Liberals appear to be running two conflicting narratives about Canning.

Foreign Minister Julie Bishop reportedly told Cabinet on Tuesday that Labor was running dead in the campaign. This prompted media speculation that Labor doesn’t want an upset in Canning to bring on a Liberal leadership change because it has a better chance against Prime Minister Tony Abbott in the upcoming federal election.

Yet the PM told the media something else altogether, insisting on Wednesday that there would be a “Labor blitz” in the last few weeks of the campaign because “Labor want this seat”.

Deputy Labor leader Tanya Plibersek (right) with the party’s candidate for Canning Matt Keogh. Photo: AAP

Mr Abbott knows there will be a strong swing against the Government in the by-election. Nevertheless, he’s hoping to convince voters to look at Canning as a microcosm of the upcoming federal election. The PM wants to be able to say: despite Labor doing everything it could to win the seat, the Liberal candidate ultimately prevailed because voters may be cranky with the Government but they still don’t trust the other mob.

As long as the Government wins the seat, the PM can feign acceptance of voters’ admonishment and promise (again) to mend his ways. But he can still claim a victory over Labor.

Accordingly, the PM can’t afford a win in Canning to be seen as merely a default decision because Labor pulled its punches. If a perception took hold that Labor ran dead in the by-election, then the responsibility for most of the swing away from the Government would firmly be placed on Mr Abbott’s shoulders.

If Ms Bishop continues to have leadership aspirations and is considering running on a ticket with Malcolm Turnbull and/or Scott Morrison, it makes perfect sense for the minister (and at least one of her colleagues) to set up the PM in this way.

Julie Bishop is playing a leadership role with Mr Hastie. Photo: AAP

The leaking of Ms Bishop’s Cabinet comments also suggests at least one minister is trying to provoke the PM to follow through on his most recent threat to make any minister found to be leaking to face serious consequences. Given that leaks are also coming from Abbott supporters – such as the weekend suggestion that the PM could ditch Treasurer Joe Hockey for Mr Morrison – any such reprimand would unleash a civil war within Cabinet.

That may be exactly what the provocateurs are aiming for.

Meantime, Labor doesn’t need to do much more than sit back and watch the squabbling. However, if the Opposition really didn’t want to win Canning or at least make the Government fight for it, it would hardly use precious campaign funds to participate in the by-election. Parties don’t devote time and resources to by-elections unless there is a tactical benefit in doing so.

Labor likely sees considerable benefit in causing grief for the Prime Minister by helping the swing against the Liberal candidate in Canning. And even more importantly, by causing the PM grief, Labor creates an invidious choice for the Liberals: should they stick with Mr Abbott and perhaps lose the election, or change the leader and face the wrath of voters who place a premium on political stability?

For this reason, of all the shadow campaigns being run at the moment, Labor’s is probably the most diabolical. However, the one being run by the anti-Abbott forces runs a close second.

Paula Matthewson was media adviser to John Howard in the early 1990s and then worked for almost 25 years in communication, political and industry advocacy roles. She is now a freelance writer and communication strategist. Paula has been tweeting and blogging about politics, the media and social media since 2009 under the pen name @Drag0nista.