When a butterfly flaps its wings in a moment of polling difficulty, billions of dollars in revenue can be lost for many years down the track, writes Annabel Crabb.

Tony Abbott has won. For the second election in a row, he has lunged determinedly through the resistant ranks of his colleagues to present something to the Australian people that most of his team-mates can't stand.

In political terms, this is quite an achievement. Especially for an Opposition Leader.

Here's the back story:

In 2007, the Howard government lost power, and one of the ministers most grievously devastated by this event was Tony Abbott, who had once described himself as the ideological love-child of John Howard and Bronwyn Bishop, though it would be difficult to establish which of these putative spiritual parents would be the more grossed-out by that formulation.

Abbott's period of mourning produced, eventually, a book - Battlelines.

The book charted a most substantial epiphany; a conversion to the cause of paid maternity leave, which was something the author had in pre-enlightenment times described (prophetically enough) as something that would happen over the Howard government's "dead body".

The book went into a second edition. Abbott became the Liberal leader.

And on International Women's Day on 2010, to the utter surprise of his own party room, he announced that the Coalition would be taxing big business to pay for a generous paid parental leave scheme.

You cannot even imagine the huffing and puffing that this unilateral announcement induced; with his substantial reserves of insouciant charm, Abbott simply apologised for springing it on everybody and observed that sometimes it was "better to ask forgiveness than to seek permission".

Ever since then, Abbott's colleagues have fussed about like parents trying to redress a toddler's self-administered haircut.

There being nothing to be done about the central problem at hand (Abbott's attachment to the haircut is absolutely implacable), other measures have been taken to reduce its visual impact.

Hence - and my apologies for taking so long to get to the point - today's announcement by Abbott that a Coalition government would cut company tax rates by 1.5 per cent, a policy timed to take effect just as his parental leave scheme is scheduled to raise them, on big businesses, by exactly the same amount.

Abbott and Hockey today describe the company tax cut as a growth measure, as a vote of confidence in the economy, and as an important force for job creation.

It may well be all those things, but it is also a beanie to cover up Abbott's 2010 home haircut, and the really interesting thing is that after three years of private whingeing, moaning, eye-rolling and pleading, no-one in the Coalition has been able to change his mind.

We all want there to be a formula to politics. For it to be predictable; for huge decisions to be bolstered, when they are made, by a substantial and unhurried process of research, reason and rationality.

The vast machinery of government itself implies the existence of complex process; all those regulations, laws and public servants must - one might be forgiven for assuming - surely add up to a halfway decent safety net against haste and impulsiveness.

Well, sometimes it works like that.

But often, it doesn't.

There is much talk now of structural deficits in the budget, and the inability of successive governments to do something permanent and sensible with the great arterial gush of mining-boom income which now wanes at an alarming rate.

The truth is that sometimes extremely large decisions are made quite substantially on the basis of human expediency.

Think back, for instance, to the last campaign in which Kevin Rudd sought government. On day two of the 2007 election campaign, there was quite an electrifying tax policy moment. John Howard and Peter Costello announced a blistering $35 billion in personal tax cuts, to be paid over the forthcoming four years.

This was quite a surprise to Rudd and Swan, who found themselves at a disadvantage. Their key tax adviser had just been hospitalised with severe chicken pox, and was only periodically available by phone from his isolation ward.

The decision to simply adopt 90 per cent of the Howard/Costello tax cuts was driven more by the political need to look identical to Howard on economic management than anything to do with the advisability of the tax cuts themselves.

Just as Scarlett O'Hara, grubbing about in the dirt for potatoes, once had cause to reflect upon her erstwhile profligacy in the frock department, I wonder if Rudd has since similarly revisited that moment, when the fear of electoral failure was so great that more than $30 billion across the out-years seemed a reasonable price for preventing it. Certainly, it's a powerful argument for compulsory vaccination against chicken pox, whatever the people in Byron Bay reckon.

Another example: March 2001, when the Howard government, struggling with the implementation of the GST, found itself in a world of pain on petrol pricing. (Pump prices hit $1. Fancy!) There was a technical discussion about the fact that the GST was applied on top of petrol excise, which in effect constituted a tax on a tax. Matters deteriorated, and the Daily Telegraph ran a front cover photograph of Howard and Costello wearing keffiyehs, under the sensitive 100-point caption, "OIL SHEIKHS!"

On March 15, 2001, after months of explaining that petrol excise was not negotiable and that it would be grossly irresponsible to cut it, John Howard made a truly remarkable announcement, at a press conference which remains the most electrifying one I can remember from all my time covering federal politics.

He announced that excise would be cut by 1.5 cents, and that the hitherto regular indexation of the excise - twice a year, calculated on CPI, regular as clockwork - would be abolished. Petrol excise has been a stopped clock at 38c a litre ever since...

Several days after that announcement, the Australian dollar slipped below the US50c mark. Just for context.

This decision now costs, more than a decade later and by my admittedly rusty calculations, somewhere around $5 billion a year. And why? Because the government was in trouble, and needed a memorable announcement.

This is political chaos theory. A butterfly flaps its wings in a moment of polling difficulty, and 12 years later you wake up and find it's costing you two-thirds of a disability insurance scheme.

Why is the study of personality in politics important? Because it's always more important than you would think. Or hope.

Annabel Crabb will be writing regularly for The Drum throughout the campaign. Annabel Crabb is the ABC's chief online political writer. View her full profile here.

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