The idea of a government exiling its citizens to a foreign land as punishment may be more reminiscent of Ancient Rome than modern Australia, but since 2015 that power has formed part of our anti-terrorism legislation which involves citizen-stripping laws.

The High Court in Alexander v Minister for Home Affairs [2022] HCA 19 recently declared that a key component of this power, section 36B of the Australian Citizenship Act 2007, is constitutionally invalid. Section 36B allows the Minister for Home Affairs to strip citizenship from anyone who is a dual national if satisfied that the person has engaged in terrorism-related conduct overseas. Revocation must also be in the public interest.

At the heart of the case was Mr Alexander, an Australian citizen by birth and Turkish citizen by descent. Mr Alexander had travelled to Syria, allegedly to join the Islamic State, before being detained in 2017 by Kurdish militia in the Deir El-Zour Province and imprisoned by Syrian officials. Based on his conviction by Syrian courts and an ASIO report that he had 'likely engaged in foreign incursions', the Minister permanently revoked Mr Alexander's citizenship in 2021. Although he later received an official pardon, at the time his case was heard he remained indefinitely detained in a Syrian prison, unable to travel to Australia and restricted from entering Turkey.

Why was the law deemed constitutionally invalid?

Under Chapter 3 of the Australian Constitution, only the judiciary, not the executive, can decide criminal guilt and impose criminal punishment. In this case, the Minister had assumed the role of both judge and jury, deciding that Mr Alexander had engaged in specific terrorist conduct and imposing punishment for that conduct. The court found that the purpose of this law was punishment, not protection, because its effect was to deprive an individual of the liberty to move freely in Australian society, just as it would if it imposed a prison sentence. The High Court found that it must be a court, rather than a minister, who decides to take away that liberty.

The High Court also expressed some concern that foreign courts do not always uphold adequate procedural protections, so using foreign convictions to support a citizenship determination is problematic. Mr Alexander had never been convicted in Australia and had made credible claims that he had been tortured and forced to sign an admission. Mr Alexander's citizenship was cancelled based on his engagement in 'foreign incursions', meaning that he had entered, or remained in, a declared area in a foreign country. However, the Deir El-Zour Province in which he was detained is not a declared area.

Citizen-stripping laws raise many concerns in relation to procedural fairness

This case raises broader questions around due process and the separation of powers, particularly with respect to expanding terrorist legislation that places limits on the rights of an accused. It's worth noting that with few exceptions, the revocation of citizenship is permanent, and gives no consideration to the possibility of rehabilitation, one of our justice system's core sentencing principles. Furthermore, the power can be used to punish conduct that occurred before the legislation came into force.

Under the sole remaining power, section 36D, the Minister may still revoke the citizenship of those convicted of specified  terrorist offences in Australia. For many of these offences, it is unclear just how effective citizen-stripping laws are at protecting the Australian community. If a person is permanently barred from returning to Australia, they are more likely to find sanctuary in places with weaker oversight and powers of investigation than Australia. This is 2022, and a person does not need to be in Australia to engage in recruitment, develop a radical ideology or incite others to engage in violence. If a person poses an immediate threat, the government has a number of alternative mechanisms to prevent return to Australia, such as passport cancellation or temporary exclusion orders.

The government is now reviewing the decision in order to determine its implications.