The High Court firmly reminded us recently of several elements critical to Australian democracy.

First, the importance of the doctrine of the separation of powers. Second, the complete independence of the judiciary, and thirdly the role of the rule of law. It did so in the case of NZYQ v the Immigration, Citizenship and Multicultural Affairs Minister – more commonly now referred to as the ‘detainee case’.

The decision in NZYQ sent a bombshell through federal parliament, leaving the government scurrying to provide answers to the Australian people, to create a new legislative regime to control potentially dangerous detainees now released from custody, and to save face when many Australians including the federal opposition now feel like we should have seen it coming.

What exactly however was decided by the High Court and why, and did the relevant ministers and the executive get it as wrong as we are being told?

The answers are to be found both in the provisions of the Migration Act and in the reasoning that led the High Court to its decision. Whilst the case was decided on November 8, the High Court did not publish full reasons until the 28th. This is not uncommon for a court when liberty is at stake. No person should be detained merely for a court to write reasons. As soon as it became clear that the government had misused its executive power, the High Court ordered the release of all detainees adversely affected, publishing its judgment later.

The provisions under consideration by the court were sections 189, 196 and 198 of the Migration Act. Summarising those sections is an insight into how immigration detention works in Australia. Section 189 provides that if a person is in an Australian migration zone and is an unlawful non-citizen, they must be detained by a Migration officer. Section 196 goes on to provide that that person must be detained either until they leave Australia, are taken to a regional processing country, are deported, or obtain an Australian visa. So far so good.

It was section 198 however that has left the Commonwealth with a major problem as a result of this case. Section 198 provides that the person is to be removed from Australia as soon as practicable. In other words, they are to be deported as soon as possible. In this case NZYQ also requested he be returned to his home country. What happens however if the detainee cannot be deported?

In defence of the Commonwealth in this matter, the High Court had already, and a long time ago, considered the lawfulness of this legislative regime. It did so in the 2004 case of Al-Kateb v Godwin. In that case, by a majority, the then High Court found that detention could be indefinite so long as the Commonwealth held the ultimate intention of deporting the detained non-citizen. It felt a bit like if the means had an end, however long that might take, the means were justified. So, what changed then?

There was no possibility of his returning to the country from where he had come. In all practical senses therefore, the detention was indefinite; without a foreseeable end

Central to the decision in NZYQ was the fact that the Rohingyan man detained was effectively stateless, with an accompanying inability to return to his original homeland of Burma. In short, there was no possibility of his returning to the country from where he had come. In all practical senses therefore, the detention was indefinite; without a foreseeable end. The Court did say that should that circumstance change the Commonwealth could re-detain NZYQ and deport him to his homeland. However, at present and at the time of the decision that seemed impossible, and the courts as a general principle do not at all like the idea that once a person who has committed a crime and has done the time, that that person should remain indefinitely in custody.

The background to this case was that NZYQ had travelled to Australia in 2012 and was granted a bridging visa. However that was cancelled two years later after he committed a sex crime against a child victim. Once his sentence was served he was refused a protection visa and ended up in immigration detention in order to be deported, and in any other circumstance he would have been. But it was practically impossible. So he stayed in detention year after year, cooling his heels. What type of detention was it then? Why was he inside?

That question led the court to deliberate on whether this type of detention was punitive. In other words did it in effect amount to a punishment? The court found that detention in these circumstances was indeed punitive, given that the sentence for the child sex offence which NZYQ had committed had been served and given that his stateless status meant that he was in effect going to spend the rest of his life in detention. The reason for it being punitive was that the purpose of holding someone in immigration detention is for the purpose of deportation. As this was not going to happen the continued detention was of a different type, namely a punitive one. If he could not be deported it necessarily followed he was there because of his past crime.

On the question of whether the Commonwealth ought to have seen this coming, there is a fair argument that it should have. That is because of the case of Chu Kheng Lim v the Minister for Immigration, Local Government and Ethnic Affairs. Lim drew a distinction between detention as a result of a judicial order, such as being sentenced for a crime, and detention on administrative grounds under, for instance, the Migration Act, which is detention other than judicial detention. The principle decided in Lim was that unless the administrative detention was for reasons other than punitive reasons, say for instance deportation, it amounted to a breach of rights under the Australian Constitution.

It was also the principle decided in Lim that caused the High Court to re-visit the decision in Al-Kateb, because the decision of that case sat uneasily with the principle in Lim.

On the face of it, Lim with its finding of unconstitutionality, might be interpreted as contrary to what had been decided in Al-Kateb. Indeed the High Court had touched on this incongruity in the past, thus it is reasonable to suggest that the Commonwealth really ought to have prepared for this eventuality. It should have prepared for the worst, and hoped for the best, because the signs were pointing towards the eventual outcome and the release from detention of NZYQ. Moreover, the High Court was unanimous in its judgment. That is to say, all justices of the High Court agreed. It is a little difficult to argue that such an outcome was entirely unexpected.

The way in which this decision has completely altered the approach in which Australia can manage immigration detention is also the reason why it will be difficult to legislate to cure the problem of having dangerous non-citizen criminals in the community. It is open to regulate these convicted criminals under alternate laws, such as sex offence laws, in order to protect the community, as it is possible to impose conditions on their release.

This is the judiciary squarely saying the executive government got it wrong. It stands for the power of law, and the rule of law

The decision in NZYQ should also not be read as meaning that a non-citizen liable to deportation is invited to remain in Australia – they are not. However, practically speaking, that is what the effect of being a stateless person results in. The practical effect means that the legal intent behind the Migration Act to rid ourselves and Australia of potentially dangerous non-citizen criminals is thwarted, and the alternative of indefinite immigration detention to protect the community is now out. It is therefore again reasonable to suggest that the Commonwealth ought to have imagined this potential scenario from the outset of the appeal by NZYQ from the Federal Court to the High Court, and prepared for its eventuality.

The decision of the High Court in NZYQ has caused anguish in the community, and disbelief across Australia. However in another sense the decision in NZYQ is a potent example of the independence of the judiciary and a victory for our constitutional rights and freedoms in Australia. It stands as a clear demonstration of the doctrine of the separation of powers at work. This is the judiciary squarely saying the executive government got it wrong. It stands for the power of law, and the rule of law. It shows that our society will not and cannot be ruled by executive government when government acts beyond its legitimacy and wields power unlawfully. Above all, and in spite of the consequences of the decision, this is a good news story for all Australians that tells us that our constitutional rights will not be trampled upon, and that we can be protected against the creep of executive government.

Unfortunately it has happened in the most horrendous circumstances, with the release of dangerous and potentially dangerous criminals, some of whose crimes have been terrible, placed back into the Australian community. Worse still, some have now allegedly reoffended. If proved, these fresh crimes allegedly committed by released detainees may have a life altering impact on victims. However courts do not pick the cases they are to hear, nor the facts and circumstances of those cases. Courts exist to uphold the rule of law irrespective of the consequences because it is principle that matters most. It is principle that preserves our democracy.

As a political headache for the government, this case and its outcome is and will remain a ticking time bomb. With each fresh arrest of one of these former detainees, the Australian community is reminded of the debacle that has unfolded, by a government doing what it ought to have innately understood was problematic: depriving an unsentenced person of his freedom, very likely for the term of his natural life. More than 140 people found themselves in that position. This, in the first world democracy of Australia. Nonetheless the cost to individuals in our community must be acknowledged and the direct impact on some Australians cannot be ignored.

That is why it is important to remind ourselves that whilst it is the politics swirling around this decision that has captured the public gaze and imagination, this is really a story about the fearless independence of law and lawyers who recognised unlawfulness and who righted it, albeit at a staggering political cost to the government of the day. It was unsurprising that the Australian Human Rights Commission welcomed the decision, even though the inadequacy of the conduct of executive government and its approach in this area of immigration law has left the community totally exposed.

Are many people concerned and disappointed by this decision? They are. Should the government and the parliament have seen it coming? They probably should have. However, the law is applied without fear and without favour and all before it are equal. In upholding the rule of law the courts cannot compromise their judgments by having regard to the consequences of a case one way or the other. To that end justice is blind, and we should celebrate its impartiality.

Morry Bailes is Senior Lawyer and Business Advisor to Tindall Gask Bentley Lawyers, past president of the Law Council of Australia and a past president of the Law Society of South Australia.