Appearing before Senate Estimates last week, Human Rights Commissioner Professor Gillian Triggs repeated her claim that gay marriage is a human right under international law.

Asked whether she was aware of Joslin v New Zealand, United Nations Human Rights Committee jurisprudence that declares the existence of no such right under the ICCPR, Triggs said she was “not familiar” with the case.

This claim is surprising given that it has featured in so many of the Commission’s submissions to federal inquiries relating to marriage. Firstly in a 2004 submission on the insertion of “man” and “woman” into the Marriage Act, and again in its 2009 and 2012 submissions on Senator Hanson-Young’s Marriage Equality Amendment Bill.

The case was described by the Commission in 2004 as “persuasive, if not authoritative in respect of Australia’s international legal obligations.”

These are the words of the same Human Rights Commission that now claims same-sex marriage is a human right under international law, citing a case that declares exactly the opposite, with approval.

What a difference a few years can make.

The Commission may fervently wish for such a right to exist, but the simple facts remain. Joslin v New Zealand is still authoritative and unchanged these few years later.

Seeing her need to take a fresh approach once the case was raised, Triggs then claimed that the right to same-sex marriage is “something that one draws as a legal conclusion from the right to equality.” Had she known of the landmark Joslin case, she would also know that it is authority for rebutting this precise proposition.

The reasoning of the case runs as follows: The right to marriage under the ICCPR is a right that applies only to man-woman unions. This is clear from the wording of the document. It is therefore impossible to claim that man-woman marriage in any way impinges on the other rights contained in the Covenant, including equality and non-discrimination. Anything less would mean the Covenant is internally contradictory; a sham.

The conclusion facing the Human Rights Commissioner is stark. Exclusively man-woman marriage stands side-by-side with equality without any conflict in the ICCPR and therefore in Australia’s international obligations. These are the obligations the Commission purports to steward.

Yet the Human Rights Commission and indeed other bodies like the parliamentary Human Rights Review Committee continually make misleading claims about the content of Australia’s international obligations.

Still seeing her need to guard against this problem in some form, Triggs did what many human rights activists do when faced with the strictures of the United Nations and international covenants that Australia has actually signed. They go on a tangent into the subject matter of other jurisdictions. Things like European conventions and long cases from the European Court of Human Rights (because that sounds authoritative). Confuse and conquer is the tactic.

But there are two problems with this approach. Firstly, these are laws of other sovereign states, with different constitutions and different legal systems, to which Australian law cannot be subject. Who ever heard of American gun laws or the Second Amendment being used as authoritative grounds to compel the Australian parliament to pursue the right to bear arms? So why do we cherry-pick their case law on equality? Or indeed the European cases, dealing with the interpretation and application of European conventions in nations like Austria, Finland and Italy?

But let me hasten to raise the second problem – the cases alluded to (Schalk & Kopf v Austria, Hämäläinen v Finland and Oliari v Italy) - don’t get activists out of their troubles anyway. Even if they could be said to bind Australia, they would not elicit either a right to same-sex marriage directly, or as a product of equality and non-discrimination rights. As recently as 2015, the European Court of Human Rights declared that there is no such reality in European human rights law.

It is disappointing that some lawyers, claiming to be impartial, routinely advise governments as if they were activists. They push an agenda that, though they wish it were true in law, is not actually true.

A great deal of authority attaches to the label of human rights lawyer in our society. Sadly it seems that, in some cases at least, the authority is being used to mask wishful thinking.