Despite sending most of its heaviest hitters into this morning’s Economics Committee Estimates hearing, the Coalition came up empty handed in its “grilling” of Treasury Secretary Ken Henry.

The grilling turned out to have all the heat of a cosy fireside chat. The attempt to find some scintilla of difference between the Reserve Bank, the Treasury and the Government on the nature of the bank guarantee came to nothing, as Henry affirmed that he and Glenn Stevens were “of one mind” on the issue of an unlimited guarantee two weekends ago and that the conversation recounted by the Prime Minister yesterday had indeed occurred.

The Coalition packed the committee with Senators Coonan, Eggleston, Brandis, Fifield, Ronaldson, Abetz, Parry and Bushby. Barnaby Joyce showed up as well, and by the time Ron Boswell, fresh from his stoush with Bill Heffernan – eminently resistible force meets immoveable object – rolled in to join the likes of Nick Xenophon and, later, Bob Brown, there were senators squeezed in right round the table.

Labor sent along Doug Cameron. Apt, perhaps – at the current rate, Cameron’s paleolithic economic views will be back in fashion by the end of the year.

Stephen Conroy, representing Wayne Swan, was there first, and cut rather a lonely figure playing with his Blackberry, until Treasury officials joined him at the last moment followed, eventually, by Henry himself. Treasury Dep Sec David Gruen read a fascinating opening statement – if you’re fascinated by such things — on the current economic environment and the pointlessness of trying to produce meaningful and useful forecasts during a crisis of unprecedented size and speed.

This confirmed what we’d previously heard from Laura Tingle in The AFR – that there were no Treasury forecasts – not even preliminary ones – that formed the basis of the Government’s bank guarantee and economic stimulus measures. Instead, Gruen explained, it was better to consider the likely risks to growth rather than wasting time trying to churn out forecasts that didn’t add anything useful to our understanding of the situation.

But bugger all that, the Coalition Senators wanted to get onto the point-scoring. Helen Coonan and Eric Abetz, at his officious best, led the charge, but that came a cropper against Henry, who seemed tired – surprisingly – and irritable at having to repeat himself every time a different combination of words was tried on him. Stephen Conroy tried to run some interference by pointing out that the entire debate was actually about what had occurred between officials and ministers, which in normal Estimates circumstances – despite whatever strange views Senate Clerk Harry Evans might harbour – is out of bounds, but Henry declared himself eager to make an exception and clear the matter up.

Eventually, Rudd and his officials might wonder at the wisdom of so readily dragging Cabinet discussions into the open for the sake of a minor political grassfire, but that can wait.

Coonan and Abetz weren’t helped by Barnaby Joyce jumping in to shift the discussion in another direction but even under the best of circumstances they would have been on a hiding to nothing. Eventually Abetz tried to get some table-banging action going over the fabricated issue of whether the Government has misled when it said the guarantee would be unlimited when in fact a cap was being considered. Even his thumps on the table lacked enthusiasm, however.

“Far be it from me to offend anyone, and especially you Senator,” Henry began drily, “ but there’s been some misunderstanding about the term ‘cap’.” He went on to explain the difference between a cap on the guarantee and a cap at which point deposits would be treated as wholesale lending and thus attract a cost to access the guarantee.

Abetz looked like Henry was speaking to him in Swahili. His Coalition colleagues, furious at failing to get anywhere, then tried to ping Henry for refusing to answer questions when he declined to detail his discussions with the Reserve Bank, and then started chasing their tails on what advice he had provided on refusing to answer questions.

It costs a lot for senators and senior officials to sit around and spin their wheels like this.