In September 2015, Malcolm Turnbull challenged incumbent Australian prime minister Tony Abbott for the leadership of the Liberal Party. Turnbull, urbane, moderate, socially tolerant, was widely viewed as the government's only chance of turning around its dismal poll numbers.

Rid of mercurial right-winger Abbott, the Liberals would power to re-election with Turnbull at the helm. The beleaguered Labor Party, now led by union fixer Bill Shorten, would take years to rebuild after its landslide defeat in 2013. The Age of Malcolm was dawning.

Then it all went wrong. Turnbull made a series of unforced errors and Shorten began to define the wealthy investor as out-of-touch with ordinary Australians. Now the polls show Turnbull just weeks away from having his tenure in the Lodge cut painfully short.

John McTernan is a veteran of turbulent Australian politics, serving as spin doctor to Labor PM Julia Gillard between 2011 and 2013. Here, he explains how the Turnbull dream ticket turned into a nightmare and how Labor stood its ground and wooed the battlers.

Australia is now at the half-way mark in its longest general election campaign since the Eighties.

Though, to be fair, it is only formally the longest since Bob Hawke in 1984. In truth, this campaign has been months long, on the cards since Malcolm Turnbull became Prime Minister last September. It had only been a matter of when, not if, Turnbull would cash in his honeymoon with an election.

The thing is, it hasn't turned out that way. The two main parties, Turnbull's centre-right Liberals and their centre-left Labor opponents, are neck and neck on 50% in the preferred vote. (Australia has the Alternative Vote system with a compulsory preferential vote choice.) This was meant to be a cake-walk for Turnbull -- his election, on his timing, to get his mandate secured. How did he end up here, faced with a real contest?

If you are new to Australian politics some background is necessary. If it had a strap line, it would probably be: "There will be blood". It's not just the brutality of the parliamentary chamber itself -- which is legendary -- but the ruthless will to win that both main parties have.

So both Australian Labor and the Liberal Party have had four changes of leadership since 2007 and the country has had six prime ministerships. Each move has been made to ensure electability. Labor's Kevin Rudd rolled Kim Beazley and won in 2007; Julia Gillard replaced Rudd and won in 2010. Liberal Tony Abbott defeated Malcolm Turnbull in the party room in 2009 and Kevin Rudd in the country in 2013.

John Howard: Katie Collins / PA Archive; Kevin Rudd: Anwar Hussein / EMPICS Entertainment; Julia Gillard: Chris Radburn / PA Archive; Tony Abbott: Chris Jackson / PA Archive; Malcolm Turnbull: Toby Melville / PA Archive.

By and large, it has worked. One exception is Rudd replacing Gillard in 2013. The fourth Labor leadership election in three years showed a party deeply divided and the voters showed Labor the door. The question of the current general election is whether Turnbull replacing Abbott as Prime Minister is another exception to the rule that ruthlessness reaps rewards.

After all, the Liberals turned to Turnbull only after a sequence of catastrophic opinion polls that showed them heading for a defeat. It was Turnbull the Winner that the party room -- the parliamentary Liberal Party -- had chosen, not Turnbull the Sydneysider and social liberal. Winning was the beginning and end of the change. And right up to Christmas last year it was all going to plan.

The country was not just relaxed -- the combination of the summer holidays with Christmas makes this the best time of the year; voters were relieved. At last the noise of politics was over. No worries about turbulence; the Liberals had chosen. No worries about being embarrassed by their PM; Turnbull was a safe pair of hands, not likely to lecture Europe on Islam or to reintroduce imperial awards like knighthoods, and try to give one to Prince Philip. The country collectively zoned out, fully expecting a general election some time and the return of Malcolm Turnbull as Prime Minister with his own mandate.

Where did it all go wrong?

It's simple really: In politics you can't defer a honeymoon to a later date. Take it or lose it. Turnbull delayed too long. But there's also the brute reality that politics is as well described by Von Moltke's aphorism as any conflict:

"No plan of operations extends with any certainty beyond the first contact with the main enemy."

Malcolm Turnbull hadn't taken any account of what Australian Labor would do. He had taken it for granted that simply by being selected by the Liberals he had beaten Labor and their leader Bill Shorten. To be fair, this was the view of most commentators and of many of Shorten's parliamentary colleagues.

One of Shorten's great advantages in his three years as leader has been the discipline and unity on the Labor side. When he had a poll lead over Tony Abbott, it was "don't rock the boat". When he was trailing behind Turnbull, it was "let him take this defeat". But Shorten had the two things which are essential in politics: Hunger and a strategy. The former is necessary but not sufficient; it is the latter which is essential.

For one thing, Shorten has learned the lesson of Gough Whitlam, Labor's greatest prime minister: Use your time in opposition to think. Gough's chaotic 1972 administration did so much in a short time -- including withdrawal from Vietnam, abolition of the death penalty, expansion of higher education, votes at 18, recognition of aboriginal rights, and opening to China. This was because he spent six years in opposition thinking.

Shorten has used opposition similarly well. He, supported by his immensely strong policy team, have thought hard about policy and, in particular, how to make cuts so that you can plausibly promise spending. Here he has been massively assisted not merely by the loyal support of his shadow treasurer Chris Bowen, but also by Bowen's intellect. Author of Hearts & Minds: A Blueprint for Modern Labor, a book which updated Crosland for 21st century Oz, Bowen adds intellectual muscle to Shorten's front bench.

For another, Shorten has been unafraid to attack Turnbull's strengths. That is the best and boldest way to win. If you triumph there then you can easily mop up the weak flanks later. Early on Shorten decided to stick to Labor's policy on carbon pricing. This was the right policy in principle for a party in favour of tackling climate change through market mechanisms.

It was also the right signal for the electorate that Labor stood for something. In the eyes of voters that was important; for them, 'If you don't stand for something, then the danger is you will stand for everything.' That decision has paid off big time with Turnbull ditching his personal positions on both climate change and gay marriage to buy the votes of his parliamentary colleagues. It didn't seem to matter in the short term, but this lengthy election campaign means that Turnbull's actions are being viewed through a longer term perspective.

Finally, campaigns reveal.

Day to day, there is an understandable media bias towards covering the government. After all, they are doing things while the opposition are only saying things. Election campaigns equalise everything. Both sides are only talking and both sides get scrutinised. To the surprise of some -- tho ugh not those who know him well -- Shorten has prospered on the campaign trail. Out is the slightly orotund figure of the standard press conferences. In is the funny, congenial, glad-handing, reactive man pounding the pavements.

The reverse has happened to Turnbull. The office of Prime Minister flattered him. His lengthy speeches and answers -- which seemed Ciceronian compared to Tony Abbott's style -- when heard every day on the news seem like the higher waffle.

Where will the country move in the second half of the campaign? The dynamic is all, ever so gently, in Labor's favour. Will that stick? It is hard to say. But it is clear that unless something turns up for him, Turnbull will be punished for inflicting a long campaign on the public. The only question now is how badly.

Comment by John McTernan, a writer, thinker, and political strategist. He has advised world leaders including Tony Blair and Australian prime minister Julia Gillard. You can follow him on Twitter at @johnmcternan.