You could hardly find a non-indigenous Australian whose roots are more deeply planted in Australia than Malcolm Turnbull. After all, he proudly descends from a staunch supporter of Captain William Bligh, an early governor.

Yet, in Israel last week, I was shown an article that raises questions about whether the Prime Minister would be considered beholden to a foreign power under Australian law.

The article, shown to me by a friend, is an old Times of Israel piece speculating about whether the Australian PM is a Jew.

“My mother always used to say that her mother’s family was Jewish,” it quotes Mr Turnbull as saying.

The Prime Minister goes on to say he has “never really looked into it” – just like John Alexander, now resigned from Parliament, had not looked into his father’s situation.

My Israeli friend would be proud if Mr Turnbull shared his religion.

“Your Prime Minister could even come here and live,” he said. This is what set off my alarm bells.

Section 44 of the Australian constitution, as we are all becoming aware, prohibits not only dual nationals from being in Parliament, but also someone who is “entitled to the rights or privileges of a subject or citizen of a foreign power”.

To be honest, if not for that section, I couldn’t care less what religion the Prime Minister holds or is entitled to. For me, I am not fussed if the Prime Minister is Christian, Jewish, Hindu or whatever.

Except, that is, for Israel’s ‘Right of Return’ and Citizenship Law, which allows Jewish descendants to settle and claim citizenship.

Under Jewish tradition, the religion extends through the female line. Hence, if your mother or grandmother is Jewish, you may be Jewish too.

The Prime Minister’s office points to an article by ANU Law Professor Kim Rubenstein – who concludes Jewish MPs do not fall foul of Section 44(i).

Professor Rubenstein’s opinion is that citizenship is not automatic. A Jew, exercising his or her rights under Israeli law, must make an affirmative act of acceptance in order to gain nationality.

Malcolm Turnbull speaks at a luncheon in February during the visit to Australia of Israeli Prime Minister Benjamin Netanyahu. Photo: Getty

But the case of Barnaby Joyce shows one need not be aware of the rights nor even seek to have these rights recognised to be invalidly elected.

Additionally the professor’s article only considers the 1950 and 1952 law, not the 1970 amendment.

In 1970 the Right of Return law was extended to cover not only those who by Jewish tradition are born Jews, but also to a child and a grandchild of a Jew, the spouse of a Jew, the spouse of a child of a Jew and the spouse of a grandchild of a Jew.

If Mr Turnbull’s maternal line is in fact Jewish then he himself may have a Right of Return and a right to apply for citizenship, even if he chooses not to exercise it.

The PM’s office says there is no evidence other than anecdotal that he has Jewish ancestry.

I do not in any way criticise the Israeli law. For people of Jewish descent these laws are indeed a good thing.

But there could be an unintended consequence for not only Mr Turnbull, but Jewish MPs including Josh Frydenburg, Michael Danby and Mark Dreyfus.

Professor Rubenstein may be right that the lack of ‘positive affirmation’ is enough to say a person does not yet have Israeli nationality, or she may be wrong. It is open to a court to rule that the right exists even if not yet exercised.

For the PM his positive affirmation of the Christian faith may have renounced his rights under the 1970 amendment to Israeli law, but what of other Jewish MPs?

Would the High Court say that in absence of a renunciation Jewish MPs have the rights even if not yet exercised, and hence are disqualified? Possibly.

I would like to be abundantly clear here: A Jewish prohibition is not an outcome I want nor am comfortable with.

If Section 44, combined with the impacts of the 1950 and 1970 laws in Israel, prohibits Jews from running then Section 44 must change.

No other comparable democracy I have found has a similar provision in its law.

Australia, where over half the population have at least one parent born overseas, should allow dual nationals to run for Parliament. The party system and the electoral process would quickly weed out a person working against national interests.

Maybe it will take the exclusion of a prime minister for us to wake up and change this law, no matter how difficult.

Andrew MacLeod is a visiting professor to Kings College London, a non-executive director to Australian and US companies, a former high level UN official and past CEO of the Committee for Melbourne. Humanitarian, author and speaker he can be followed on @AndrewMMacLeod.