COMMENT:

The clock is now officially ticking on Simon Bridges as leader of the National Party.

It doesn't mean he'll lose the job this week, this month, or even this year. But he'll be gone eventually.

How can Bridges stop the inevitable? He needs to find whoever it is that leaked details of his expenses. Then, if it's someone in his party, punish that person severely.

The problem for Bridges is this saga makes him look weak. Impotent even. He can't figure out who leaked the details, he can't compel the police to give him the name they have, and he can't even prevent Speaker Trevor Mallard from calling off his inquiry into the leak.

Bridges is powerless. Just like every other Leader of the Opposition before him. Pretenders to the throne but until then unable to tell anyone what to do. Not even their own caucus half the time.

And while that's not unusual, it's not helpful to have it pointed out. To everyone. So blatantly.

To solve this, Bridges needs to find out who sent the text. Who texted Bridges, Mallard and two media organisations claiming to be a National insider? Claiming to have leaked the expenses story to punish Bridges for arrogance and wasteful spending of taxpayer money? Pleading for Mallard's inquiry to be called off, warning they had mental health issues and could be tipped over the edge if publicly exposed.

Guessing who the leaker is is impossible. Because, quite frankly, everyone looks guilty. Still, there are two realistic scenarios.

The first scenario is that the leaker is someone in Labour. The motivation's there. Nearly a year on from the election, it must frustrate Labour no end that National is still hugely popular. Surely Labour must be looking for any way to scare voters off.

But, that's a big call because it would mean Mallard has breached the long-standing tradition of Speaker's neutrality. A speaker shouldn't play favourites. A speaker should become something of a political eunuch. Turned on by no one.

Still, it's curious that Mallard called off the inquiry into the leak on Friday. Just the day before, he'd been all guns blazing, appointing Michael Heron QC to head it.

So why call it off? Nothing had changed overnight. Mallard had had the text for a week at least. The only new information was that police knew who it was and were confident the leaker had the mental health fortitude to handle the inquiry.

The second, and most likely, scenario is that someone in National leaked it.

The motivation is that Bridges isn't popular with voters. Someone might think they'd do a better job.

It's suspicious that the texter provided details of National Party caucus conversations. It's also suspicious that Bridges hinted all his MPs might not consent to having their electronic devices searched.

Still, he wants an inquiry. Albeit an inquiry that might not access all National's computers.

Unless we know who leaked it, the suspicion falls on National's caucus. That suggests the kind of division and instability that National has tried so hard to avoid.

National has aimed for absolute discipline. That's the best way to look like a government in waiting. It's the easiest way to get re-elected in 2020.

That's at risk of evaporating. And Bridges has to take the blame for this. The only reason this has happened is because he pushed for an inquiry. He should never have done that.

The original story about him spending $113,000 on crown limos wasn't the end of the world. It would've been fish and chips paper within half a week tops. But now it's dragged on and it's so much bigger. It's a bad judgement call.

It might be possible for Bridges to tough this out. But it might also require a sacrifice: the leaker. But to do that Bridges needs to find them.