If politically disengaged Western Australians are aware that a state election is being held next Saturday, chances are they have the Chamber of Minerals and Energy to thank.

Since early November, free-to-air television has been saturated with advertisements in which a series of ordinary Joes denounce a proposed new tax on a mining industry, which, notwithstanding an acknowledged recent downturn, is said to hold the key to the state’s future prosperity.

Even before the formal campaign period began, the cost of the advertising was put at $2 million — well on the way to what a major party would ordinarily expect to spend over the full length of an election campaign.

Only with the quickening of the campaign tempo over the last week has either party’s advertising matched the visibility of the mining industry’s.

In tone and content, the ads are all but indistinguishable from those unloaded on the Resource Super Profits Tax when Kevin Rudd unveiled it six weeks before the termination of his leadership in June 2010.

Aside from the very specific details of the policy being denounced, the only observable distinction is the political target — not the Labor Party this time, nor even its rival in the race to form government after next Saturday.

Instead, the mining industry sledgehammer is being applied to the walnut of the National Party, which has again illustrated the independence of mind peculiar to its Western Australian state branch by offering a brave strategy to tackle a public debt forecast to reach a dizzying $40 billion in 2019-20.

[Poll Bludger: WA Liberals starting to sweat]

This involves increasing a lease rental rate paid on iron ore production by BHP Billiton and Rio Tinto from 25 cents a tonne to $5 — finally adjusting for inflation a rate that had effectively gone unchanged since it was set in the early 1960s.

It is promised that this will add as much as $2 billion to government revenue annually, assuming the correctness of inevitably contested assumptions.

The policy bears all the stylistic hallmarks of party leader Brendon Grylls, whose remarkable electoral achievements over the past decade largely reflect his success in imposing the Royalties for Regions scheme on the Barnett government.

This reserves a quarter of the state’s mining royalty revenue for regional projects, and would itself be first for the chop under any rationally ordered scheme to restore the budget to health, if either major party dared countenance it.

But whereas Royalties for Regions offers a politically happy confluence of thinly spread pain and thickly concentrated benefit, the loser this time around is the most powerful enemy that anyone in Western Australian politics could contrive to create for themselves.

Even so, the initial reception appeared positive, with a ReachTEL poll in September finding 45.4% in support and 31.5% opposed — suggesting the public now takes a much more sceptical view of the mining industry than it did when federal Labor’s ill-fated tax plans were launched at the peak of the boom.

But when the same pollster repeated the exercise after two months of the ad campaign, support was found to have dropped to 34.8%, with opposition up to 39.0%.

The Chamber of Minerals and Energy further cranked up the psychological pressure on Grylls late last year by releasing results of two privately conducted polls from Pilbara, the formerly Labor-held seat to which Grylls audaciously moved in 2013 as part of a successful strategy to break the party out of its wheat belt heartland and into the then-prospering mining regions of the state’s north and deep interior.

[WA election micro-party form guide: the ultra-marginal and just plain weird]

Both showed Grylls in third place, with the implication that the Liberals would win the seat ahead of Labor after the distribution of his preferences.

In late January, however, the Nationals countered with a very different internal poll of their own, showing the Liberal vote tanking and Grylls headed for much the same winning margin over Labor he achieved in 2013.

Either way, there are a number of reasons to think the mining industry can rest easy so far as Grylls’ tax policy is concerned.

Every other party of consequence, including One Nation, is vehemently opposed, and it is highly unlikely that the Nationals will emerge from the election in the formidable bargaining position they enjoyed in 2008, when they held the balance of power in both houses of parliament.

Ultimately, the industry has a bigger objective in mind than simply seeing off a policy proposal from a marginal player like the Nationals — a point made abundantly clear by its massive advertising spend in Perth, where the party isn’t even fielding any candidates.

It’s to ensure that no political party, major or minor, ever loses sight of the fact that any endeavour to draw more revenue from the industry will come at a heavy political cost.