Yes, it's a bizarre, almost inexplicable mistake. But will this really register, out there in the electorate? Will the next election really be decided on Treasury accounting errors? After all, surely nobody today, not even the senator herself, could really believe any government forecasts, could they? If that's the best "gotcha!" moment Labor can come up with, perhaps Scott Morrison will win the next election, after all.

January seems a very long time ago, now.

Back then Labor's Mike Kelly was busily pushing (yet another) proposal to shape this country's future. He was enthusiastic, embracing the detail, the small stuff, because he knows that all the little cogs have to work smoothly together. Unless that's happening the gears will crunch and problems compound. That's why he became a politician - he wanted to contribute and get things running smoothly.

Kelly knows climate change is altering our environment and that's why, through the smoke and heat of the fires, he saw an opportunity to change society for the better. He was proposing a volunteer "army" to develop the resilience we so desperately need to face this new threat. His proposal needed work, of course, but at least he was out there trying to solve the problem. Kelly saw government could do something and achieve what we couldn't as individuals.

His structure could also be easily developed and repurposed to combat other enemies - like coronavirus. And even if you didn't like his particular answer to this urgent and emerging problem, at least give Kelly credit for coming up with ideas to make our lives, and society, better.

I don't know what happened to his proposal within the party, but instead of being embraced by the so-called leadership group Kelly's idea appears to have fallen on barren ground. That pretty much seems to encapsulate Labor's approach these days. The virus should have provided a marvellous opportunity for the opposition to shine a light on what's really important - relationships, communities and society. It's a chance to remake society. Big ideas are meant to be Labor's strong suit. Instead we get nonsense about budget deficits.

Quibbling about financial figures won't change any votes.

I haven't spoken to Kelly since he announced he was quitting. Apparently his health pushed him to go, and I can believe that. Nobody would willingly put themselves through the nightmare of campaigning for Eden-Monaro without some reward - like the certainty you could make a difference in government - at the end of it. He claims he still believes Labor will win. I'm sure he would deny that it's the party's bureaucratic approach that pushed him towards his decision to quit. It really doesn't matter now. He worked hard for Labor. Nobody should begrudge him leaving at the time of his choice.

Kelly wasn't the sort of person who'd sit back and rely on "the swing" to get elected. That's how he turned the seat into his own between 2007 and 2013, and seized back the ultimate marginal bellwether seat from the Coalition in 2016. Kelly worked the huge area as it expanded and took in new booths that traditionally returned conservative majorities. But this is also why his decision to leave is so important.

As I've made clear, I accept at face value his statement that he is leaving for medical reasons.

When Kevin Rudd recruited him back in 2007, however, Kelly (like that year's other wonderful star recruits that seemed to promise so much and Maxine McKew, or locally Gai Brodtmann and Andrew Leigh) represented - or seemed to represent - a vigorous new direction for the party. Rudd worried about the detail, which is why he'd pushed hard to get people he wanted in particular seats. This challenged the comfortable and long-standing union hierarchy insisting everyone shut up, toe the line, and wait to be promoted.

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In the end, of course, Bill Shorten got rid of Rudd, and the old apparatus regained control. Perhaps unsurprisingly, this doesn't seem to have worked out particularly well so far.

If you're attempting to work out who will secure victory at the next election, you'd typically look at the government. That's because two pretty reliable rules of thumb have emerged to illuminate the path to victory. The first is simple: "oppositions don't win elections, governments lose them". The second is more subtle: "slowly, inevitably, support seeps away from the party in power". Voters turn to the opposition as the party in office fails to deliver on promises.

Earlier this year Labor was, understandably, stoked. Even if the Coalition (again) threw buckets of public money at electors in marginal seats, it seemed impossible they'd win. After all, Scott Morrison had just scraped in last May, securing a majority of just two seats; what could possibly overcome the slow, inexorable, ebbing of his tide, that had only just pushed the conservatives across the line?

Politics looks very different today.

Labor put all its eggs in one basket, relying on the drift and ignoring the detail. Shorten made exactly the same mistake last year.

Yes, we all know Morrison's victory was a fluke, but the moral is never to assume victory is in the bag. What's needed to guarantee political success is hard, detailed, painstaking, electorate work, coupled with vision for a different future. Oh, and great leadership.

Do you see that on either side of politics today?