Julia Gillard has received considerable criticism for her comments on Chief Justice Robert French and the High Court’s decision in the Malaysian offshore processing case. On Friday, Justice Philip McMurdo, on behalf of the Judicial Conference of Australia, declared that the Prime Minister’s statement was “extraordinary, unfair and curious” and suggested that she may have “upset the balance of separated powers”, which is essential to the operation of a free society.

But such criticism is over the top. Judges constantly comment on actions of the executive government as well as legislation passed by the Parliament. It is only reasonable to assume that, on other occasions, members of the executive and parliamentarians will see cause to comment on judicial decisions.

These days many judges and ex-judges weigh into the public debate when they choose. Earlier this year a number of senior Victorian judges saw fit to defend County Court judge Felicity Hampel, whose judgments had been criticised by a journalist. Hampel has made three appearances on the ABC TV Q&Aprogram and should be able to look after herself. In June last year, French also agreed to be interviewed for a profile by James Eyers in the Australian Financial Review Magazine.

Judges who become involved in the public debate either on or off the bench – or who see fit to move into an area once regarded the preserve of government or Parliament – should not be surprised if they then cop criticism. Considered criticism of the judiciary is not necessarily an attack on the separation of powers and may, at times, serve as a useful reminder that such separation is a mutual obligation.

In the wake of the Malaysia offshore processing case, the Prime Minister was entitled to express surprise that French’s judgment seemed inconsistent with decisions he made when on the Federal Court. Justice Dyson Heydon, in his dissenting judgment, cited two Federal Court decisions in which French found that the government had the right to send asylum seekers to another country.

Heydon made the important point that “the largest single part of the Federal Court of Australia’s work is migration law” and that “it has incomparably greater experience” in this area than the High Court.

Heydon cited six one-time Federal Court judges, including French, whose decisions he regarded as authority for the validity of the Gillard government’s proposed asylum seekers swap with Malaysia.

In his judgment, French did not address the decisions he made when on the Federal Court.

French was appointed Chief Justice of the High Court by the Rudd government in 2008 following the retirement of Murray Gleeson. As a young man, French was active in the Liberal Party but was never ideological. He was appointed to the Federal Court by the Hawke Labor government and to president of the National Native Title Tribunal by the Keating Labor government.

Some senior members of the Rudd government believed that James Spigelman, the then NSW chief justice, should have been appointed to succeed Gleeson. However, it seems that Rudd was intent on appointing French.

No one doubts French’s qualifications. However, the evidence suggests that – unlike Gleeson – French is heading up an activist High Court. In the Australian Financial Review, which appeared on August 15, journalists Alex Boxsell, Samantha Bowers and Hannah Low cited experts as declaring that the French High Court “is gaining a reputation for striking down laws, frustrating contentious government policies and delivering novel and innovative judgments”.

University of NSW academics George Williams and Andrew Lynch, who are not opposed to judicial activism, have also reached a similar conclusion.

In a paper titled The High Court on Constitutional Law: The 2010 Term, the pair argue that the French court marks a “significant change” from the Gleeson court. Williams and Lynch depict the French court as taking on the Commonwealth and the states by a process of “undoubted constitutional creativity”. This is legalese for judicial activism.

The ideal approach to asylum seeker policy is for Australia to have a red flag out the front and a green flag at the back. This is where the Howard government ended up. It was seen to be extremely tough on unlawful boat arrivals but, by the end of John Howard’s prime ministership, there were only a few asylum seekers in detention.

The Rudd government took down Howard’s red flag and replaced it with an amber one. Little wonder, then, that the boats started arriving again in significant numbers. And now, in the Malaysia case, the High Court appears to have overridden the Gillard government’s attempt to put out its own red flag and replaced it with a green one.

The problem with an activist judiciary is that it does not have to handle the consequences, intended or unintended, of its own decisions. Labor MP David Bradbury was entitled to say on Sky News last week that “it won’t be members of the High Court that take the phone call that Chris Bowen had to take after a boat crashed into the rocks at Christmas Island” last December.

There is reason to be sympathetic to asylum seekers. But reason, too, to understand that permanent residence in Australia is a glittering prize for which men, women and children will risk their lives by travelling in unsafe boats after paying a small fortune to people smugglers. So there is good reason to discourage unlawful boat arrivals.

In the main judgment in the Malaysia case, justices William Gummow, Kenneth Hayne, Susan Crennan and Virginia Bell seemed to suggest that they would not strike down offshore processing in Nauru since, in such a circumstance, Australia would remain responsible for asylum seekers. However, the Solicitor-General, Stephen Gageler, has advised that he is not confident this would be the case if the matter was to be tested in the High Court.

The problem with an activist High Court is no one can be sure where the action stops.

Gerard Henderson is executive director of The Sydney Institute.