The past week has certainly reinforced my personal suspicion that Four Corners is now the sole effectively functioning arm of the federal government. Everywhere else, breathtaking incompetence rules.

Really, it didn't need to be this hard. We don't usually hear much about the Commonwealth Attorney-General, whose main job is to oil the legal wheels of government. Instead, George Brandis has made an art form of turning simple tasks into disaster, then doubling down and making things worse.

Thanks to George, the universally acclaimed decision to establish a fast-moving royal commission to investigate the Northern Territory's juvenile "justice" system devolved almost instantly into a mismanaged farce.

When picking a royal commissioner, you only have to keep in mind the famous legal maxim from a 1924 English case, that "justice should not only be done, but should manifestly and undoubtedly be seen to be done".

What this rule of natural justice recognises is the obvious: that a system of justice can only function effectively with the implicit confidence of the community whose interests it exists to protect. That confidence is built on a foundation of perceived independence, impartiality and fair dealing. In a world of imperfect knowledge, perception takes its place alongside factual reality. If the perception is tainted, the foundation is weakened.

Practically, this means that judges and other empowered decision makers must be not only without any actual bias or prejudgment, but free of any fairly grounded perception that they may be so infected.

The perception, or "apprehended bias", test is "whether a fair-minded lay observer might reasonably apprehend that the judge might not bring an impartial and unprejudiced mind to the resolution of the question the judge is required to decide".

The balance sought by this formulation is to disregard the conspiracy theorists and partisan complainers, while listening to the concerns of impartial non-lawyers; that is, the reasonable citizen who just wants to be confident that justice will be done, uncorrupted by bias.

Brian Martin, the former NT chief justice who was the government's first pick as royal commissioner, had endured several days of intensifying attacks on his selection before doing the obviously right thing and resigning his letters patent with the dignified and accurate statement that:

"It has become apparent that, rightly or wrongly, in this role I would not have the full confidence of sections of the Indigenous community which has a vital interest in this inquiry. As a consequence, the effectiveness of the Commission is likely to be compromised from the outset. I am not prepared to proceed in the face of that risk."

That's a perfect recitation of the apprehended bias rule. As Martin went on to note, he did not personally accept that he could not do the job, nor that the assertions of apprehended bias against him were fair or reasonable. However, his point was well made: his mere presence was dooming the Royal Commission before it even started.

The taint of apprehended bias circling Martin had two facets. First, as chief justice he may be seen as too close to indigenous justice issues, particularly given his court’s involvement in specific cases that may come before the commission. As Crikey reported last week, the NT Supreme Court in 2014 upheld the not guilty verdict of a guard at Don Dale who had been accused of assaulting Dylan Voller, the prisoner whose image, cuffed and hooded in a restraint chair, is now globally infamous.

Secondly, Martin's daughter had worked as a justice adviser to a former attorney-general, during a period falling within the commission's scope of inquiry.

All of this should have been known and obvious before Martin's appointment. It should have been more than enough to remove him from consideration.

This Abbott-Turnbull governments have made four royal commissioner appointments, and got it unarguably right just once; that was the 2013 pink batts commission, ironically itself a complete waste of time and money but presided over by an unimpeachable commissioner.

The other three have been Dyson Heydon of the Royal Commission into Trade Union Governance and Corruption, Brian Martin, and Martin's replacements.

Heydon got into a world of pain over his acceptance of a speaking engagement at what turned out to be a Liberal Party fundraiser. Heydon ultimately ruled that a fair-minded lay observer would not think him biased. The result was that Bill Shorten and the unions got a free pass on what might have been some damning findings had they issued from a commissioner who nobody thought might be a secret Coalition supporter.

Which brings us to the replacements for Martin as commissioners for the NT inquiry: former Queensland Supreme Court justice Margaret White and Social Justice Commissioner with the Human Rights Commission, Mick Gooda. White is beyond reproach -- an excellent appointment and, hooray, a woman.

Gooda's appointment should also be the cause for celebration, because of his tremendous reputation and experience, and for the fact that he is an indigenous Australian. But for one thing: in the heat of the reactions when the Four Corners story first broke, Gooda tweeted "The Federal Government has to intervene and sack the NT Government", following up the next day with another tweet: "Elfernick sacked Prisons Minister but still the AG, are they seriously telling us he will be negotiating the ToRs for the Royal Commission?"

Gooda also made public statements at the time, including this:

"Let's have another intervention and put an administrator in the Northern Territory cos it looks to me like they're incapable of managing anything up there."

These were perfectly understandable sentiments and Gooda had every reason and right to stand up and express his views. He has nothing to retract or defend, although he sought to retreat from his comments once he had been appointed as a commissioner.

Unfortunately, the horse has bolted. If the rule against apprehended bias operates in favour of indigenous people and victims of the juvenile detention centres, then it must equally be applied to protect those on the other side of the fight; the Northern Territory government, its agencies and those who work in its justice and prison system are entitled to know that their cases have not been prejudged.

It is regrettable in the extreme and not, in any respect, his fault, but an allegation of perceived prejudgment may be fairly levelled at Mick Gooda. The rule against apprehended bias is not concerned with whether Gooda is actually biased or not, nor whether he will be able to separate his initial emotional reaction, as he now describes it, from the rational impartiality required of a royal commissioner. The fair-minded layperson has good reason to be unsure about that, and to apprehend that Gooda may have prejudged some of the central issues he will now be required to consider.

Again, this should have been known and it should have disqualified Gooda. Those charged with nominating the royal commissioners have performed their role with remarkable incompetence, with the disappointing consequence that the commission will embark on its work under a shadow.