The Australian Human Rights Commission’s report into children in immigration detention is out, and the findings are clear. The prolonged and mandatory detention of Australia’s “forgotten” asylum seeker children causes “significant mental and physical illness and developmental delays, in breach of Australia’s international obligations”.

The inevitable next question is: who is responsible?

The commission’s inquiry touched on the Immigration Department’s duty of care to all persons in immigration detention, and the Immigration Minister’s failings as the guardian of around 56 detained unaccompanied children. The larger issue, though, is who is legally responsible overall for the harmful impact on children of Australian refugee law and policy.

Whereas Australian courts usually approach this question through the lens of domestic law, the commission’s mandate was to “assess whether laws, policies and practices relating to children in immigration detention meet Australia’s international human rights obligations”. This shift from a domestic to an international law perspective raises three important points about responsibility.

First, the question of responsibility for violations of international law goes beyond matters of politics. For the purposes of international law, it is irrelevant which government first introduced a policy, or chose to maintain it. On the international plane there is only one entity: Australia.

Second, international law determines the scope of Australia’s obligations. In relation to responsibility for the treatment of children detained on Nauru, the commission’s report describes an intractable argument with the Immigration Department as to whether these children fell within the commission’s mandate. Ultimately the department refused to provide the information requested about these children, and the commission ran out of time to pursue the point.

Legally, this deadlock is not unresolvable. The question of who is responsible for human rights violations in Nauru is determined by objective criteria established by international law. The broad consensus among international law experts is that this responsibility rests either exclusively with Australia as a result of its “effective control” over detained asylum seekers on Nauru, or jointly with Australia and Nauru as a result of their collaboration in operating the detention regime.

Further, the law of state responsibility sets out the scope of Australia’s obligations concerning the actions of private companies and individuals. Australia may be accountable for the actions of government officers or private contractors who engage in or condone the mistreatment of children, regardless of whether those actions also give rise to individual criminal responsibility.

Third, Australia’s obligations under international law extend to a duty to provide an appropriate remedy for any harm suffered by children in immigration detention, regardless of whether it was the state or a third party that caused it.

The commission’s recommendations should be considered in light of this third point, in particular the recommendations to establish a royal commission, provide access to government funded mental health support, appoint an independent guardian for unaccompanied children asylum seekers, and take immediate steps to release children from detention.

After a discussion of legal responsibility, the final question often asked is: who can enforce international law if Australia chooses not to comply? There are various international avenues that could be explored, but as a democratic country based on the values of fairness and human dignity, we should look closer to home first. The commission’s report has identified each of the areas in which Australian refugee law and practice is falling short of international standards in relation to children. It is now for the other institutions of this country to act to remedy these deficiencies — the Prime Minister and his cabinet, the Parliament, the judiciary and, most importantly, the Australian public.