By signing on to support a minority Gillard Labor Government, Tasmanian Independent Andrew Wilkie may very well have also signed his own political death warrant at the next election.

The Federal Liberal Party is furious at Wilkie's decision with the fury that only a sense of betrayal can bring forth. The explanation for the backlash is simple; Wilkie was elected in Denison on August 21 on, wait for it, Liberal preferences.

The former Greens candidate and Liberal Party member polled a meager 21.3 per cent of the primary vote. Labor's Jonathan Jackson was on 35.8 per cent. Then came the Liberal's Cameron Simkins on 22.6 per cent and the Greens Geoffrey Couser on 18.9 per cent. As such Simkins how to vote card directed his votes to Wilkie.

Wilkie was a political fluke. If the Greens had managed just 3 per cent more of the primary vote they would have finished ahead of Wilkie and also been elected on Liberal preferences ahead of Labor.

Given the Greens' new formal alliance with Gillard Labor, that result would not have altered the outcome of the current minority government negotiations. The Greens Adam Bandt, who won the seat of Melbourne, also from Labor, is supporting Gillard. So too would have the Denison Green, Jonathan Jackson.

But for the Liberals none of this matters. All that counts for them is that Wilkie got over the line with their backing and has now rubbed their noses in it. The next election will bring revenge.

Senior Tasmanian Liberals who spoke with The Drum on condition of anonymity said that at the next election - which they're expecting within 18 months - The Liberal Party would take the remarkable step of preferencing Labor in Denison. Under those circumstances Wilkie would be wiped out, a one term wonder.

And if he thought he was going to get any favours out of Labor in return for backing Gillard he should think again as well. Denison is regarded as a "natural" Labor seat. They lost it on August 21 because they pre-selected what one senior Liberal described as an "appalling" candidate in Jackson.

"He was the son of a former Tasmanian Attorney-General," says another local Liberal. "They thought that would be enough. It wasn't. They took the seat for granted and ran a bad campaign to boot.

"That won't happen next time. They (Labor) will throw the kitchen sink at it."

There's nothing to suggest this analysis is other than prescient. Given the knife edge August 21 result the next election, which most inside observers think will be well inside the full term agreed to between the Greens and Gillard, is going to be one where both major parties will be going all out to win.

It will be dog eat dog and there'll be no favours for past service. Labor won't want Wilkie in the Parliament just as much as the Coalition won't. He will be hammered by both sides. Under these circumstances can he survive?

If the voters of Denison want an independent member with a strong belief system, Wilkie is not their man. He has been on both the Left and Right of Australian politics. Early in his life Wilkie graduated from the Duntroon military college rising to the rank of Lieutenant Colonel.

In a twist of fate, the Liberal candidate in Denison on August 21, Cameron Simkins was at Duntroon at the same time. He and Wilkie were friends and it was that friendship that at least, in part, helped build the Liberal preference deal that put him over the line.

Turning his back on Simkins in favour of Gillard has simply added more fuel to the Liberal fire when it comes to Wilkie.

After Duntroon, Wilkie, who has admitted belonging to the Liberal Party "many years ago" worked for US Defence giant Raytheon. Hardly a soft Left outfit. He continued his defence career as an intelligence analyst with the Office of National Assessment. Soft Lefties also need not apply.

In 2003 he broke onto the national stage when he resigned and spoke out against the Howard government on the Iraq war, saying there was no intelligence to indicate Saddam Hussein had weapons of mass destruction.

This event seemed to mark Wilkie's conversion to the Left. At the 2004 election he ran against then incumbent prime minister, John Howard in his seat of Bennelong as a Greens candidate. He also ran for the Greens on their Tasmanian Senate ticket in 2007. After falling out with Brown he resigned from the party in 2008 citing a lack of "professionalism".

Some close to the Greens believe wasn't the Greens professionalism that was the issue, but more Wilkie's ego. At the 2004 election, fresh from his spectacular exit from the Office of National Assessment and following a high profile campaign against the Iraq War and then his personal "war" against Howard in Bennelong, Wilkie was extremely high profile.

By the time the 2007 election campaign came around he was just another losing Greens candidate. Some say it rankled.

Wilkie then opened a rug shop in Hobart and washed up in Denison. He is in effect a serial candidate. And his win on August 21 was narrowly founded. Senior Tasmanian Liberals say it was based in part on a positive and at times moving profile on "Australian Story". The Denison demographic is regarded as very ABC.

The second factor in play is a characteristic limited to Tasmania called the "sympathy" vote; a phenomenon whereby candidates in that state who fail at one election have a history of being regularly voted in at the next. Examples: Labor's Michelle O'Byrne who was dumped by voters as the Federal member for Bass in 2004. She then contested the next state election, won the seat of Braddon in a landslide and is now Health Minister in the Bartlett Government.

On the Liberal side, Michael Ferguson won the seat of Bass in 2004 - from O'Byrne - but lost it in 2007. He too is now in the state Parliament. Having lost as a Green's Senate candidate in 2007 Wilkie fits this model.

His politics have changed remarkably. From being a national interest whistleblower in 2003 he's now firmly rooted in parish pump politics, after that other famous pork bareller on behalf of Tasmania, former Independent Senator, Brian Harradine.

In welcoming his support for her minority government, Julia Gillard, congratulated Wilkie on putting the "national interest" first. What tosh. She gave him $340 million for a new Hobart hospital. That's a hefty price tag for one vote.

As a result, says one Tasmanian state Liberal, "He''ll be popular for a while. "But it's a long way from 20 per cent to 50 per cent."

That's a reference to the next election in Denison where Wilkie will have to get 50 plus one per cent of the vote not to have to rely on Liberal preferences. Otherwise he's gone. And in politics the numbers never lie.

Glenn Milne has been covering Canberra politics for more than two decades.