Section 36B of the Citizenship Act invalid?

Some of the questions to the High Court (HCA) were as follows:

Question 1: Can it be said that, although alienage is a constitutional concept, "s 51(xix) of the Constitution empowers the Parliament to "create and define the concept of Australian citizenship", to select or adopt the criteria for citizenship or alienage and to attribute to any person who lacks the qualifications prescribed for citizenship "the status of alien""?

Question 2: Is the term "non‑citizen" as used in the Migration Act 1958 (Cth) synonymous with "alien", as the latter term is used in the Constitution?

Question 3: If an alien becomes a citizen but their citizenship is then cancelled, are they then aliens?

Question 4: If the answer to Questions 1 to 3 is 'yes', does that mean that Parliament may "expand its law‑making power under s 51(xix) of the Constitution by pursuing an eccentric understanding of alienage"?

Question 5: If the answer to Question 4 is 'yes', is it fanciful to classify as an alien "an individual who, though previously a citizen, has acted so inimically to Australia's interests as to repudiate the obligations of citizenship on which membership of the people of the Commonwealth depends"?

Question 6: If the answer to Question 5 is 'no', is voluntary conduct, as described in s 36B(5)(h) ("engaging in foreign incursions and recruitment", which is defined as entering or remaining in, a declared area in a foreign country such as the al‑Raqqa Province in Syria) "so reprehensible as to be incompatible with the common bonds of allegiance to the Australian community, even though the person who has engaged in that conduct did not act intentionally to repudiate the bonds of citizenship"?

Question 7: Item 18 of Schedule 1 to the Australian Citizenship Amendment (Citizenship Cessation) Act 2020 provides that a determination may be made in relation to conduct specified in s 36B(5) that was engaged in before the subsection commenced. If the answer to Question 6 is 'yes', does s 36B(5)(h) have retrospective effect?

Question 8: Can it be said that s 36B of the Citizenship Act "reposes in the Minister the power to adjudge and punish criminal conduct by involuntary denaturalisation", which is "an exclusively judicial function, and not one which fell within any established exception bringing it within the acknowledged remit of the executive"? In other words, does s 36B offend the separation of judicial power under Ch III of the Constitution?

Question 9: If the answer to Question 8 is 'yes', is the consequence for a person who voluntarily does the acts described in s 36B(5)(h) different in substance from the punishment meted out pursuant to s 36D?

Question 10: Can it be said that, "traditionally, an analytical distinction has been drawn between a legislative purpose that is "penal or punitive" and a legislative purpose that is no more than "protective" in the context of determining whether a law infringes the doctrine of separation of judicial power by conferring on a decision-maker other than a court a power to detain – or, more broadly, a power to constrain the freedom of action or to revoke or suspend the statutory status of – a person found to have contravened a statutory norm"?

Question 11: If the answer to Question 10 is 'yes', 'will' a punitive purpose be incompatible with the doctrine of the separation of judicial power, whereas a protective purpose 'may' be compatible with the doctrine, as a protective purpose may still pursue that purpose in a manner incompatible with the doctrine?

Question 12: Can it be said that the attempt "to analogise from a purpose of upholding standards to be expected of those who by choice engage in a profession or in an activity involving an element of public trust, or in radio or television broadcasting under statutory licence, to a purpose of upholding standards to be expected of all Australian citizens in virtue of them being Australian citizens must be rejected"?

Question 13: Can it be said that "determining whether a law infringes the doctrine of separation of judicial power, to say no more than that the purpose of a law is to protect the Australian community from an Australian citizen found to have contravened a statutory norm is to say nothing to indicate that the law has a purpose that is "protective" in a sense meaningfully distinct from a purpose that is "penal or punitive""?

Question 14: Can it be said that "a legislature of limited powers "cannot arrogate a power to itself by attaching a label to a statute" and cannot, merely by including a statement of purpose in legislated text, require a court to identify the purpose of a law as something that it is not"?

Question 15: If the answer to Question 14 is 'yes', can it nevertheless be said that "the constitutional relationship between the judiciary and the legislature is such that a statement of legislative purpose must be treated by a court as a solemn and presumptively accurate declaration of why a law is enacted"?

Question 16: Parliament chose to explain the purpose of the whole of the subdivision within which s 36B is included under s 36A. Can it be said that, "translated to the level appropriate for analysis of the compatibility of s 36B with Ch III of the Constitution, the purpose declared in s 36A is properly characterised as one of denunciation and exclusion from formal membership of the Australian community of persons shown by certain conduct to be unwilling to maintain or incapable of maintaining allegiance to Australia"?

Question 17: If the answer to Question 16 is 'yes', can it be said that, as s 36B is limited to criminal conduct found to have been engaged in by a person in the past with the result that "the purpose of denunciation and exclusion from formal membership of the Australian community is solely on the basis of past criminal conduct", that purpose can only be characterised as "punitive"?

Question 18: If the answer to Question 8 is 'yes', may the position well be different in respect of certain laws dealing with denaturalisation?

Question 19: If the answer to Question 18 is 'yes', can it be said, by way of example, the "in respect of a law conferring power on the Minister to cancel a person's citizenship if they obtained citizenship by making false statements or engaging in fraudulent conduct, denaturalisation might be more properly characterised as the consequence of breaching a condition imposed on the person's entry into the community, rather than punishment"?

Question 20: Has the High Court already "recognised that a person born in Australia to parents of whom at least one is a permanent member of the Australian community can be a constitutional alien"?

Question 21: Was s 36B of the Australian Citizenship Act 2007 (Cth) invalid because it is inconsistent with an implied limitation on Commonwealth legislative power preventing the involuntary deprivation of Australian citizenship?

Question 22: Was s 36B of the Australian Citizenship Act 2007 (Cth) invalid because it effects a permanent legislative disenfranchisement which is not justified by a substantial reason?

The HCA answered those questions as follows: