If truth is a politician's strongest currency then predicament Green Party Co-Leader Metiria Turei is in is a prime example of what happens when that truth is challenged, or is not all that it seems to be.

Her admission of benefit fraud gave her party's welfare policy a heft and cut through it would not otherwise would have had. There is, after all, nothing better than speaking from experience to convey a message.

On that score, the reasoning was sound.

Where it fell down though, was when subsequent events and details undermined the strength of the original story. If you take Turei's original position at face value which I, and no doubt others, did then you were left with the impression of a young mum doing her best to provide for her child. Subsequent information regarding the relationship with the father, her living with her mother, and support from the extended family, suggest the situation, while certainly difficult was not as fraught as first impressions suggested.

The other damaging aspect is the enrolment issue. At face value for Turei to have the same address as her child's father suggests more dishonesty. Her explanation around the election, wanting to vote for a friend may well be plausible, and not remembering the matter because it was so long ago may well be the truth. But the damage is done.

Labour's Kelvin Davis has made the point that if you bring these issues up then you better tell the whole story. For various reasons Turei didn't, and it left her exposed. Exposed to challenges to her credibility, and exposed to pressure from the Labour Party who'd been left wrong-footed and frustrated by the traction the Greens had been getting on the issue.

It's been interesting to see how the Labour-Green MOU has stood up throughout last week's events. The hard nosed attitude of Labour towards the Greens in the last few days shows that when push to comes to shove the MOU works when up to a point, but in the end the self-interest of politics reigns supreme.

I'm not suggesting Turei deserves to be hung drawn and quartered for things she did quarter of a century ago. All of us have shadows in our past that we would not be proud of were they exposed now. But, it's how we, and especially MPs, handle them when they are that matters. Past indiscretions can be understood and forgiven. To not be fully up front about them when they are exposed will cause headaches.

And that is the predicament Turei is now in.

Her Co-Leader James Shaw can talk as much as he likes about the Green Party's potential to change the welfare system in a future Labour led Government. But the fact remains Metriria Turei won't be the Minister to do it. Out of the entire Green caucus she was the best qualified for the job, and now she'll be stuck on the sidelines. For Turei and her party that will be a tragedy.