The analogy between union leaders running fundraisers for slush funds and a supposedly impartial Royal Commissioner attending a Liberal Party fundraiser is imprecise, but the short shrift Dyson Heydon gave unionists' excuses is instructive, writes Paul Karp.

Trade Union Royal Commission chief Dyson Heydon has a difficult judgment to make in coming days - whether his own actions in agreeing to speak at a Liberal Party fundraiser gives rise to actual or perceived bias that should disqualify him from his role.

And who better to judge these actions than the former High Court Justice himself? And what better standard than the one he has set for others at his own Royal Commission?

Before we consider his actions, let's start with what we know. In an email sent just yesterday morning, Heydon's personal assistant said he would be unable to give the Garfield Barwick address "if there is any possibility the event could be described as a Liberal Party event".

It sounds a bit like he refused to attend. But there's more to it. The email from Liberal identity Gregory Burton tells Heydon:

As you know [my emphasis], although nominally under the auspices of the Liberal Party lawyers' professional branch, this is not a fundraiser - the cost charged is purely to cover dinner including our guests ... although of course people will disclose it if they go over the state donation limit.

So there you have it. The Liberal organiser of the event took it as given that Heydon knew it was a Liberal event and despite asserting it was "not a fundraiser" he immediately told Heydon attendees may have to declare the $80 fee as a political donation.

Burton's email seeks to reassure Heydon: the event is not open to media; he will not be asked about the union Royal Commission; there will be no party attribution in the Bar News record of the address. Reassuring Heydon there was no good reason he should not attend, even though he is presiding over a Royal Commission which has grilled two leaders from the other side of politics.

Burton also foresees that potential problem, saying the organisers had proceeded on the basis Heydon would fulfil the commitment "even though the Commission is still in hearing (not expected when originally arranged)".

NSW Liberal state director Tony Nutt said Heydon was approached to deliver the address "several years ago". But from Burton's email it sounds like when it was "originally arranged" the Commission was already in train, but it was expected to have concluded when Heydon gave the address in 2015. This suggests Heydon may have accepted the invitation to speak some time in 2014 after his appointment to the impartial role but before the Commission was extended by a year.

And remember, Heydon's caveat that he could not give the address was expressed only as "at least while he is in the position of Royal Commissioner", thus reserving the right to speak at Liberal events after the job is over as he would be entitled to do.

Royal Commission case studies

There have been several case studies in his Royal Commission examining attendance at union-organised fundraisers. Although the analogy between union leaders running fundraisers for slush funds and a supposedly impartial Royal Commissioner attending a Liberal Party fundraiser is imprecise, the short shrift he gave unionists' excuses is instructive.

In the TURC interim report, Heydon found then Australian Workers Union (AWU) Victorian secretary Cesar Melhem used his name to "deliberately target the custom" of employers so they would attend a function believing it was an AWU event when in fact their money went to Melhem's Industry2020 slush fund. Heydon found Melhem became a "generous benefactor" contributing to union elections, including of officials at other unions who helped him win Labor preselection for the Victorian Upper House. He said Melhem's path was "truly charmed" and "it could not seriously be contended" that the donations "did not have some role to play" in securing "a privileged path to office".

In a similar case study Heydon criticised the AFL Grand Final Breakfast run by a union slush fund, which was advertised by a flyer saying Building Industry 2000 Plus Ltd "together with the CFMEU" put on the event. This implied it was a union event, when proceeds went to the slush fund, he concluded.

In these examples when examining unionists' conduct, Heydon knew that big names can pull a crowd and if you want to know whose interests the event organisers were acting in you have to follow the money. Shame he didn't apply that scrutiny to the Garfield Barwick address.

Any concerns Heydon had about whether the Garfield Barwick address "could be described" as a Liberal event could have been assisted by reading the invitation advertising it. The invitation carried a NSW Liberal letter head, asked for payment to the NSW Liberal Party, and stated "all proceeds from this event will be applied to state election campaigning".

If only he'd seen the invitation, this whole mess could have been avoided. Arguably he already knew enough because the email he had received said the event was "under the auspices of the Liberal Party lawyers' professional branch" and might require political donation disclosure from its attendees.

Any witness coming before TURC in such circumstances would have been grilled about whether they were only concerned if the event "could be described" as a fundraiser - or were they recklessly indifferent to the fact of whether or not it was one?

There's more than enough to argue apprehension of bias on Heydon's part, and it's the reason why his toughest examination may be the one he has to conduct of himself.

Paul Karp is an industrial relations journalist at Thomson Reuters. Find him on Twitter @Paul_Karp.