Heather du Plessis-Allan: Jacinda Ardern fails big test after Labour camp scandal

Jacinda Ardern is nowhere near as powerful as Helen Clark was.

Can you imagine Labour Party apparatchiks ever keeping a secret from Helen Clark? Especially a secret as big as allegations of sexual assault on youth at a Labour-run summer camp?

Me neither.

Even if she was new to the job like Ardern, Clark would have been told.

Labour HQ says its reason for keeping the incident secret from the Prime Minister was to protect the young alleged victims. They say they didn't want the 16-year-olds further traumatised by fearing the story was spreading.

I don't buy that.

Firstly, the 16-year-olds didn't need to know Ardern was told.

Secondly, regardless of whether you believe Labour was trying to protect the kids — or protect itself by covering up the story — there is one obvious point at which the Prime Minister definitely needed to know. That point was when the Labour Party bosses knew the story was about to hit the media.

At that point, Ardern should have been told. The Labour suits should have realised how Ardern would look when confronted by media who knew more than she did. At best she looked like her own party won't trust her with top secret information. At worst it looked like her own party is scheming against her.

They should have protected her. But they didn't. Why?

In my view, there may be a power battle going on inside Labour most of us aren't aware of. I wasn't aware of it until I stumbled across it last year. It became so fascinating that I wrote an 11,000-word thesis about it at university.

The battle in my view is between party president Nigel Haworth and the Prime Minister.

In the Labour Party, the party president has as much power as the Prime Minister. This is one of the quirks of the party. The president has enough power to force Labour MPs to follow his instructions by passing party rules.

When MPs get badly out of line, the president's part of the party deals with the discipline. Not the Prime Minister.

In my view, Haworth may have asserted himself as party president. He knows how much power he has, and he's putting some of it to use.

It was different under Helen Clark. She was the boss and then-president Mike Williams followed her orders.

Clark ran the country and the Labour Party. Ardern only runs the country. Under her, the Labour Party is a force unto itself.

Judging by the summer camp debacle, the party has the power to hurt the Prime Minister. And it has done just that.

In the past week Ardern still had a chance to prove herself. She could have shown Haworth, Labour and the country who's boss. Possibly, the only way to do that was to demand a head.

The head is Andrew Kirton's. He was donkey deep in this debacle. He was told of the alleged sexual harassment four days after it happened. It was under his watch the victims weren't offered help until three weeks after the event.

Demanding a head would also have told New Zealand parents the Prime Minister takes this seriously and won't tolerate this kind of stuff-up.

But Ardern took no scalp.

Is that because she doesn't think the issue was a big-enough stuff-up to demand a resignation? Or is it because she hasn't the power to claim a scalp?

You can't help but think Kirton wouldn't have survived under Helen Clark.

• Heather du Plessis-Allan is on NewstalkZB Wellington, weekday mornings.