Julia Gillard did not just announce an election for September 14 in her first big speech of 2013. She challenged the whole Australian political system to assume a new level of maturity, transparency and integrity.

She held out the prospect of an election that would be fought on the basis of economic reality; one in which all parties have seven months to set out their policy prescriptions and make the numbers add up. An election in which the media get the chance to actually analyse the promises, instead of just trailing around on a bus from one stunt announcement to the next. An election in which the policy wonks can potentially wield as much influence as the psephologists. An election, most importantly of all, which challenges the voting public to make more-informed decisions.

This is a good thing.

Let’s not pretend, though, that the gambit was not motivated by political calculation. Gillard and her people would obviously have worked out that it plays to her strengths.

The polling shows the public don’t much like her, don’t see her as a warm person, but do see her as smart, tough and capable of getting things done.

The people don’t like Tony Abbott either, but for different reasons. Not that he’s too cold, but that he’s too hot — negative and aggressive. The government has devoted a lot of energy to reinforcing that perception over the past year or so.

In fact, in 2012, according to a Global Mail analysis of the Hansard record, Labor members and senators used the words “negative” or “negativity” 433 times in relation to Abbott and his side. One hundred and fourteen of those references were made by Julia Gillard herself.

We know this tactic was effective, because the Coalition has lately made a big deal of the fact that in 2013 Abbott will “flick the switch to positive”, as Sydney’s Liberal-friendly Daily Telegraph put it in an Australia Day piece.

Evidence of Abbott’s positivity was a promise to create two million jobs, while also “delivering a surplus in his first, second and third year as PM, based on present economic conditions”.

Ambitious, huh? Two-and-a-half times as ambitious, in relative terms, as Republican presidential candidate Mitt Romney was when he promised that if elected he would create 12 million jobs in the United States.

Comparisons with America are suddenly relevant, because the long campaign Gillard has now set Australia on is very like the long campaigns waged in America, in which every promise is fact-checked, truth-squaded and modelled to establish its credibility.

And look what happened to Romney’s promise of 12 million jobs. It was torn apart by independent analysis. Just as his tax plans were.

Against the odds, in spite of a flat economy and general climate of disappointment with President Obama’s slow progress in fixing things, Obama came from behind and Romney lost because he was not credible.

With her election announcement, Gillard has set a double trap for Abbott. If he stays negative, the government will say he’s scared to reveal his true policy agenda. If he goes positive, he must show that his agenda is feasible by spelling out details.

As things stand now, the Coalition will have a lot to do to establish the feasibility of its various thought-bubbles of policy.

These are tough times to be in government. They are not like the Howard years, during which the revenue was rolling in faster than ministers could shovel it out in electoral bribes.

Part of the tactical brilliance of Gillard’s speech to the National Press Club was that it did not offer bribes.

She started by saying the speech would “take a warts-and-all look at who we are today and the opportunities and risks which confront us”.

And that is what she did. She spelled out exactly how tough things are: the amount of tax collected from all sources — particularly from company tax — is significantly lower than independent forecasters or the Treasury had anticipated.

“Compared to the public revenue which was forecast on the eve of the global financial crisis in 2008, what has actually been collected in tax since is far lower — on average, lower by more than $30 billion every year,” she said.

“Even compared to what was forecast once the worst of the global financial crisis had passed, annual revenue is tens of billions of dollars below what was expected.

“With pressure on revenue, it is the wrong time to be spending without outlining long-term savings strategies which show what will be foregone in order to fund the new expenditure.”

She promised that the government would do that. To implement education reform, it would find balancing savings. To implement a national disability insurance scheme, it would do likewise. And people would see, in the May Budget, how the savings were made.

Her challenge was for the Opposition to do likewise, to submit its policies for Treasury costing, to see if the figures add up.

The Opposition response was to send out its manager of Opposition business in the House, Christopher Pyne, to obfuscate — which could be read as an indication that they know the policies would not pass muster.

And no wonder. They have said they would abolish the mining tax, perhaps not such a big deal because it seems not to be raising much revenue anyway; and that they’d nix the carbon tax, which would be a big deal.

In place of the carbon tax we have the ill-considered idea of a direct-action plan, which, instead of taxing polluters, which yields revenue, would pay them not to pollute — which costs revenue.

The Opposition has offered no costing. The progressive think tank The Australia Institute puts it at $11 billion.

The Opposition promises not to touch the ridiculously generous superannuation tax concessions for high-income earners, which are growing like topsy.

We could go on, but you get the picture. Absent huge countervailing savings, it does not add up.

The traditional way for governments to approach an election is to set out their agenda at a campaign launch, only a couple of weeks — sometimes just a matter of days — before polling day. But Gillard has effectively launched Labor’s campaign seven months out, and promised to flesh out all the details in the May budget, four months from polling day.

The traditional way in which opposition parties approach an election is to adopt a “small target” strategy, keeping the details of its agenda under wraps until the campaign launch, and then fleshing them out only after they win.

This is pretty easy to do in a normal election campaign, which lasts just a few weeks. There are no parliamentary sittings. Analysis is minimised. There is a great deal of colour and movement to distract from issues of substance.

The question now is, how long can the Coalition parties resist providing details before they start to look shifty?