Heather du Plessis-Allan: Steven Joyce's exit a big blow for National

New National Party leader Simon Bridges has made his first mistake: losing Steven Joyce.

You may not like Joyce. He's a polarising figure.

If you're inclined to vote left, you might resent him for his $11.7 billion fiscal hole claim. You may believe it was no more than an election campaign fib and that the Labour Party's budget never was short of that much coin.

If you're inclined to vote right, you may believe Joyce's claim. You may think it's only a matter of time before he's proven to have been correct.

Either way, he is invaluable to National. And that's because he single-handedly stopped Jacindamania. He's the only person in that party who knew how.

Joyce arrested Labour's relentless climb in the polls in the last weeks of the election campaign by dropping the fiscal-hole bomb. Then when the tactic began to backfire, he stepped in and took full responsibility. That meant it hurt his reputation only, and spared then-leader Bill English's.

The reason Joyce knew how to arrest Jacindamania was that he is a master at running campaigns. By 2017, he'd already run National's past four general election campaigns.

So that's what just walked out the door. Five campaigns-worth of experience.

And on top of that, National voters like Joyce. He's a familiar face and voice. He's been on their radios and TVs at least weekly. Sometimes a little too unkind to his opponents, but mostly he was jovial. Voters liked that.

In fact, when voters were asked who should lead National after English's departure, Joyce's name was one that popped up most often.

So, Bridges would've been wise to have done something, anything to keep Joyce. In the best-case scenario, he should have kept him as an MP, but popped him somewhere reasonably out of sight so as not to taunt left-leaning voters. Former leader John Key did something similar with Murray McCully who also had something of the dark ops about him. Worst-case scenario, Bridges may have had to give Joyce the finance role. And truly, if it came down to a choice between Joyce and Amy Adams — who did get the role — Bridges might've been wise to opt for Joyce.

The problem is Joyce is unpopular in the caucus. Tough biscuits. That shouldn't be a reason for Bridges not to give Joyce finance. That's the kind of school-yard bickering leaders need to manage.

Joyce's loss isn't the only problem National has.

Bridges' own appointment signals a lack of courage. There were two courageous alternatives at either end of the generational gap.

At the old-guard end, there was Collins. A known face, tough enough to punish Labour, but at high risk of punishing her own team as hard. At the new-generation end of the scale there was Mark Mitchell. New enough to be fresh to the public, settled in enough to know what he's doing around Parliament but at high risk of messing it up by peaking too early (aka Doing a David Shearer).

Instead, National chose Bridges, who is neither a rip-the-heads-off leader nor real generational change.

If anything, you could say he's a phoney. He's not the young, fresh thing he may look. His views are classic old-school Conservative: anti-euthanasia, anti-marijuana liberalisation, anti-abortion law liberalisation and he even voted against same-sex marriage.

There's a good chance previous National voters will now take a look around and realise the other side isn't that bad. I'm picking a looming drop in National's up-until-now rock-solid polling.

That's not Bridges' biggest problem. His biggest problem is figuring out how to claw that support back. It's going to be harder now that Mr Fixit, aka Steven Joyce, is gone.

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