An “Undemanding” Standard – Materiality and Reasonable Conjecture on Lost Opportunities
Nathanson v Minister for Home Affairs  HCA 26
Mr Nathanson’s visa was mandatorily cancelled on character grounds under s 501(3A) of the Migration Act 1958 (Cth). A delegate of the Minister for Home Affairs decided, pursuant to s 501CA(4), not to revoke the cancellation decision. Mr Nathanson sought a review of this decision in the Administrative Appeals Tribunal (AAT).
Before the AAT hearing, the Minister obtained two police reports of family violence involving Mr Nathanson. In addition, Ministerial Direction No. 65, which guided the evaluative decision under s 501CA(4), was replaced by Ministerial Direction No. 79. The new direction added paragraph 13.1.1(1)(b), which provided that “crimes of a violent nature against women or children are viewed very seriously, regardless of the sentence imposed”. When the hearing commenced, the Tribunal member gave Mr Nathanson a marked-up copy of Ministerial Direction No. 79 showing the changes but noted that they were only “minor” and of “minor relevance” to his matter.
In closing submissions, the Minister raised a new issue, namely: that the police reports read in light of the new paragraph 13.1.1(1)(b) necessitated the conclusion that Mr Nathanson had been involved in violent conduct against his wife that was “extremely serious”. The AAT relied on the domestic violence incidents, among other matters, in affirming the delegate’s decision. At no point had the Tribunal drawn this new issue to Mr Nathanson’s attention, and he had not made submissions or presented evidence on the two incidents.
The decisions below
An application for judicial review and an appeal to the Full Court of the Federal Court of Australia were both unsuccessful. On appeal, Steward and Jackson JJ (Wigney J dissenting) held that, while a denial of procedural fairness was admitted, Mr Nathanson had not established jurisdictional error as he had not shown the materiality of that denial – i.e., he had not identified matters that could have been put before the Tribunal which showed a realistic possibility of a different outcome.
The question for the High Court was: what did Mr Nathanson have to show in order to establish the materiality of the denial of procedural fairness, and therefore jurisdictional error?
The High Court’s decision
All members of the High Court accepted that (to the extent he had to) Mr Nathanson had established materiality by pointing to the possibility that he could have presented more about how the domestic violence incidents were to be evaluated. He did not have to show any specific evidence or submissions he could have put on.
Four separate judgments were given, adopting a spectrum of approaches to the threshold of materiality.
Chief Justice Kiefel and Justices Keane and Gleeson applied MZAPC v Minister for Immigration and Border Protection (2021) 95 ALJR 441, holding that, to establish materiality, an applicant must prove, on the balance of probabilities, the historical facts necessary for the court to be satisfied, as a matter of reasonable conjecture, of the realistic possibility that a different decision could have been made had there been compliance with the relevant condition on the exercise of the statutory power: . Their Honours held that the standard of “reasonable conjecture” is “undemanding” and will generally be satisfied where an applicant was denied an opportunity to present evidence or make submissions on an issue that required consideration. The standard proceeds on the assumption that a party will take advantage of any fair opportunity to present their case and does not require proof as to how they would have used any lost opportunity: .
Justice Gageler largely echoed the plurality: –, . His Honour added that, where the procedure adopted by a decision-maker can be shown itself to have failed to afford a fair opportunity to be heard, unless there is something in the historical facts from which it can be inferred that the decision could not have been different, meeting the reasonable conjecture standard “will not be difficult”: .
A different emphasis: Gordon J and Edelman J
Picking up what was said by the majority in MZAPC, Gordon J held that there are certain categories of error for which a separate onus to establish materiality does not arise. This includes an error that is so egregious that it will be jurisdictional regardless of its effect on the decision: . The very nature of such an error demonstrates that an inherently valuable opportunity has been lost: . Her Honour considered that the Tribunal’s denial of procedural fairness to Mr Nathanson was such an error: .
Justice Edelman held that only in an exceptional case should a decision made without procedural fairness remain valid: –. For Edelman J, the question of whether a threshold of materiality needs to be satisfied comes very much last in a sequence of three distinct inquiries: 
First, has the applicant established a denial of procedural fairness capable of producing “practical injustice”?
Second, if there was practical injustice, was the denial of procedural fairness sufficiently serious that it was, without more, material?
Third, if the denial of procedural fairness was not so serious, has the applicant established that it could have made a difference to the result?
Justice Edelman, like Gordon J, would in Mr Nathanson’s case have answered “yes” to question 2: . However, were it necessary to consider question 3, Edelman J held that, given that an applicant bears the onus on this question, to prevent materiality eclipsing the guarantee of procedural fairness, the threshold must be one of “almost nothing”: . An applicant need only establish that, but for the denial of procedural fairness, there might have been things that they might have said at the hearing that might have assisted their case in a manner that might have led to a different result: , .
The majority’s decision in Nathanson clarifies the threshold of materiality established in MZAPC, at least in respect of denials of an opportunity to be heard. However, uncertainty remains as to when materiality is a requirement of jurisdictional error.