Burdened though it may be by a moribund economy and stagnant population, Tasmania can at least take comfort in the long shadow its affairs cast over national politics.

Tasmanian environmental issues have been placed high on the national agenda at least since the Franklin Dam controversy of the early 1980s, and in Brian Harradine and Andrew Wilkie the state has twice had its interests advanced by independents holding swing votes in federal Parliament.

This tendency may be emerging again as the aluminium industry pleads for a full exemption from the Renewable Energy Target. Nowhere does this notion resonate more than in Tasmania, home to one of Australia’s five aluminium smelters at Bell Bay, which consumes no less than a quarter of the state’s electricity.

The smelter’s location in the north-east of the state places it in the electorate of Bass, which holds the remarkable distinction of having changed hands at six of the last eight elections.

The 25 government backbenchers who this week signed a letter to Environment Minister Greg Hunt calling for the exemption included all three of the state’s lower house Liberal MPs — Andrew Nikolic from Bass, along with Eric Hutchinson and Brett Whiteley from its no less electorally sensitive neighbours of Lyons and Braddon.

The matter is also disturbing the equanimity of the Palmer United Party, with Tasmanian Senator Jacqui Lambie dissenting from Palmer’s headline-grabbing change of heart on the RET last week.

The issue serves as a reminder of the state’s weight of parliamentary numbers, which include as many senators as New South Wales despite having only 7% of its population, along with the constitutionally mandated minimum of five House of Representatives seats, without which it would only be entitled to three.

Furthermore, its voters appear to have developed a knack for making themselves noticed.

This was evident as long ago as June 1975, when the Bass by-election portended the demise of the Whitlam government four-and-a-half months later.

More recently, the Liberals snared Bass and Braddon in spectacular style after John Howard outmanoeuvred Mark Latham on forestry policy during the 2004 election campaign, and achieved a clean sweep of the three hitherto Labor-held northern Tasmanian seats in September.

Tasmania’s various electoral convulsions feature common threads that will give the Abbott government a lot to think about as it maps out its strategy for a re-election it can no longer take for granted.

A strong blue-collar workforce kept northern Tasmania in the Labor fold for most of its wilderness years in the 1950s and ’60s, but this constituency has become increasingly difficult to manage as Labor has relied more on support from migrant communities and urban progressives in the face of declining union membership.

This has proved to Labor’s cost when it has been perceived as too close to the Greens, as was demonstrated yet again by the double-digit swings it suffered at the state election in March.

However, northern Tasmania voters have proved themselves more than willing to revert to Labor type when the right hip-pocket issue comes along, as they demonstrated at the GST elections of 1993 and 1998.

So it can be imagined what kind of feedback the three Liberal MPs have been receiving in the wake of the May budget from constituents who are grappling with a local unemployment rate of around 8%.

To the extent that the fate of the three seats looms in the government’s calculations, an opportunity to wedge Labor on the future of one of the state’s ailing industries would seem to have a lot to recommend it.