As Prime Minister Jacinda Ardern deals with Australia's Prime Minister Scott Morrison over the case of a so-called Isis bride returning to New Zealand, she may be thinking of the phrase "fool me once, shame on you. Fool me twice – shame on me."
The citizenship debate over Suhayra Aden has been a bone of contention between Ardern and Morrison since Morrison ambushed her by stripping Aden of her Australian citizenship without warning.
In short, he played her for a sucker.
The issue became public in February this year, when Aden was detained with her two children while crossing the border from Syria to Turkey.
Aden was born in New Zealand, but moved to Australia when she was 6 years old. She became an Australian citizen, and left Australia for Syria in 2014, travelling on her Australian passport.
She had two children in Syria and was taken in custody while crossing the border from Syria to Turkey.
Ardern had believed she was working in good faith with Australia over what might happen if Aden needed to return.
She was furious when she learned Australia had revoked citizenship behind her back.
She told Morrison she would express that if Aden's case became public.
But Morrison will be unrepentant about the decision to leave Aden to New Zealand, despite his show of cushioning it with almost meaningless reassurances about the future.
Morrison, like his successors, was always going to be an immovable force over such as issue.
It was easier to tell Ardern she was lumped with the issue, rather than tell Australians he had agreed to let someone he described as "an enemy of our country" retain Australian citizenship when there was another option.
The argument Ardern had put up was similar to the argument put up against Australia's deportations policy for criminals.
It was that someone who had lived in Australia since a child was more of an Australian than a New Zealander. They were radicalised in Australia, and the family and support base were in Australia.
A similar argument has been put up by successive New Zealand Prime Ministers over the deportees issue, and rejected by successive Australian Prime Ministers.
It was inevitable the same argument about Aden would fall on deaf ears.
Let's face it, it is more than likely the exact same outcome would have resulted in Aden's case even if Australia had stayed in talks and given notice.
New Zealand does not have the same legal provisions to remove citizenship as Australia, nor the same political will to buck its international reputation. Australia is often criticised for its law allowing it to revoke citizenship.
Morrison put on something of a show of pretending to re-consider the Aden case, saying on his visit to New Zealand in May that they were discussing the situation of the children.
Ardern has since indicated Morrison had agreed to consider treating the children differently to the mother. It remains unclear what that means and is still under discussion.
Ardern has said she tried to persuade him to revisit Aden's citizenship, but to no avail.
She remained adamant Aden was Australia's responsibility, but New Zealand was left with no choice but to take it.
All Ardern secured was a commitment that if similar cases arose in the future, Australia would consult before removing citizenship.
It falls well short of a commitment that Australia would not make the same move. It is little more than a heads-up accord. It may also be tested before long.
Suhayra Aden may well not be the only case the two countries have to deal with.
Back in 2016, the then Prime Minister John Key came under fire after SIS head Rebecca Kitteridge revealed New Zealand women were heading to Syria to become so-called "Jihadi brides."
The Opposition claimed Key was simply scaremongering, and deliberately withheld the detail that the women had actually left from Australia – not New Zealand.
To counter it, PM John Key argued that it was irrelevant where they left from – the issue was where they would return to.
His point was that if the time came for them to return, if they were New Zealand citizens New Zealand would end up with them.
The Aden situation has proved that point at least, although the numbers of those "Jihadi brides" was never revealed by the agencies.
The Government is now clearly hoping that if several others in Aden's position end up being sent back, the two countries will share the load.
Experience should caution the Government against holding out too much hope.