Northern Ireland's Renewable Heat Incentive (RHI) scheme is a debacle. "Debacle" is not my word, it is the one Arlene Foster chose when making her infamous statement to the Northern Ireland Assembly before Christmas. If debacle is the right word, then it's because one definition is "a complete failure, particularly because of poor planning and organisation".
It's important for a number of reasons. First, there is the additional projected cost. That could be as much as £600 million above and beyond the £660m the Treasury was happy to fund. The excess costs lie with us, as a devolved government. In other words, it comes out of the block grant, currently at a rate of £85,000 a day. How ironic, after all these years of blaming every ill on Tory austerity, that the DUP put an additional squeeze on our beleaguered finances.
The second reason RHI matters is because it exposes a flaw in our governance structures at Stormont. Mrs Foster rightly told us some weeks ago that an Executive minister was charged with policy, not detail, and that she could not be across every "jot and tittle" of her department's work programme.
Unfortunately, this does not defend her against this debacle, because she signed off on a series of policy decisions: to seek the devolution of renewable heat policy when it rested with the Department of Energy and Climate Change in London; the decision not to cut and paste the successful RHI scheme already operating in Great Britain; and the politically fatal decision to adopt a Northern Ireland-specific scheme that failed to build in the cost controls that applied elsewhere in the UK, such as degression, an exotic sounding term that, simply put, means if there is a pound available and one person applies, they get the pound, but if 100 apply, they get one penny each.
Plus, Mrs Foster wrote to the local banks in early 2013 in terms more akin to an over-zealous financial adviser than an Executive minister, telling them they were on to a good thing if they were lending to anyone wishing to buy a renewables boiler. The assurances were staggering in their certainty, demonstrating an awareness of the "jot and tittle" of the RHI scheme.
Emma Little-Pengelly MLA attempted a defence of Mrs Foster on BBC Radio Ulster yesterday, pointing out the flaws were missed by many, including officials, energy specialists, the statutory scrutiny committee and the Assembly itself.
She might have added special advisers, but did not, perhaps because there is at least anecdotal evidence that places a question mark over the motivation of some.
For Mrs Little Pengelly, there is an awkward distinction between Mrs Foster and the rest. It is the concept of ministerial responsibility. Mrs Foster was the minister; the minister is the department.
The third reason RHI is important is because it has further undermined public confidence in the integrity of the devolved institutions.
Although the DUP has a history of political scandals, I sense RHI is different because everyone instinctively understands this one, and they are angry - 'cash for ash' does not sit well with ever-lengthening NHS waiting lists, Troubles victims seeking pensions to compensate for lost life opportunities and the elderly facing the winter dilemma of "heat or eat".
Of course, the DUP has accused me of simply seeking a scalp. I am not. I am focused, as all 108 of us should be, on the fact Stormont is now held in contempt by a worryingly large proportion of our population.
Look at the voting patterns for Assembly elections: 70% in 1998, 64% in 2003, 63% in 2007, 56% in 2011 and 55% last year. This is about leadership. Mrs Foster leads the Executive and Assembly as First Minister. The public look to her for an example. As they reflect on the use of petitions of concern to protect Executive ministerial colleagues for due process, they question what is more important: individual careers, or the integrity of the institutions? My answer is the latter, and if Mrs Foster agrees, then the only honourable course of action is to resign.
It is, as a certain generation would put it, "the done thing". Nothing should be more important than prioritising the reputation of the Assembly and its Executive arm.
It is for that reason, and that only, that I feel Mrs Foster should step down. It would be a strong, selfless statement that would help transform public perception, especially if complemented by three other important actions: a judge-led, time-bound public inquiry under the 2005 Inquiries Act; the passing of Westminster legislation to introduce a windfall tax that would recover excessive profits; and the introduction of cost controls for the RHI scheme from today forward.
Sadly, judging by her comments in yesterday's Belfast Telegraph, Mrs Foster is more focused on fighting to save her job. No doubt encouraged by special advisers like Timothy Johnston, she has engaged in classical political deflection.
There is not a shred of evidence that she is subject to misogyny from any political opponent, but it does nudge the focus of the debate somewhere less uncomfortable for her.
I accept she may be trolled on social media, we all are. It's not nice, it reflects something fundamentally unpleasant about some elements of society, but there is a simple cure if you are offended or hurt - block the trolls.
Mrs Foster also had what some think was a swipe at me over mental health. I have campaigned on this issue since I was elected, partly because of the experience of trying to support my wife as she suffered through clinical depression over 20 years ago, and also because of my experience as a Commissioner for Victims and Survivors, so many of whom endure severe wellbeing issues. Of course, politicians are not immune from developing mental health issues, but that does not excuse us from the rough and tumble of public service.
I do not complain when Mrs Foster calls me part of "Steptoe & Son" or throws personal insults across the floor of the Assembly.
I simply repeat my call for the Executive to take big, bold steps to address the fact that Northern Ireland has one of the worst per capita rates of poor wellbeing in the world.
The ultimate deflection, however, seems to be that to criticise Mrs Foster is to undermine unionism. She tells this newspaper my calls for her resignation are not playing well with unionists.
I beg to differ. At the supermarket on Monday, the woman at the check-out looked at me: "I had such high hopes for Arlene," she sighed.
This is not about unionism, any more than it is about mental health or misogyny.
Yes, some unionists will not like one unionist leader criticising another, any more than the DUP will like two DUP ministers attacking each other on BBC NI television.
But what this is about is ministerial responsibility, good governance, the integrity of the devolved institutions, the standing of Stormont in the court of public opinion and the need to properly and fearlessly examine why waste on an industrial scale was allowed to pass. To try to deflect from these real, important issues by playing the sectarian card is wrong.
If there is a silver lining to this debacle, it is that it should push us closer to my aspiration of a post-sectarian society, where the political issues are headlined by the economy, the education of our children, housing, and our precious National Health Service - normal politics, where mistakes are made, and responsibility is admitted.