In a surprise announcement, the shadow finance minister Amy Adams will leave parliament in 2020, and has stepped down from her frontbench roles with immediate effect. Alex Braae asks what happens now 

It could have all been so different for Amy Adams. True story: one of my first assignments at The Spinoff in 2018 was to write an explainer on the new National leader. Trying to stay ahead of the news, I wrote up a profile of Amy Adams. She lost, and the piece never saw the light of day. Simon Bridges appointed her in the critical role of finance spokesperson. Some still talked about her as a compromise candidate to replace Bridges if he continued to flounder in the polls.

But she’s put an end to all and any speculation on that front, by announcing today that she’ll quit politics at the next election, waving goodbye to the Selwyn constituency – where she commands the country’s biggest majority – and resign her frontbench role immediately.

It hasn’t been an easy year and a half since the election for the opposition. Simon Bridges’ journey through purgatory has meant squaring up against one of the most popular PMs in modern history. And Amy Adams has had the misfortune of coming up against one of the most fiscally cautious Labour governments in history. The Budget Responsibility Rules have blunted what would typically be easy attacks around wasteful spending. While some commentators have pointed to Amy Adams as something of a weak link for the opposition, it’s arguably hard for anyone to hit such a small target.

So with Adams gone and the finance portfolio now open, who is in line to step up? There are a few credible options, some more likely than others.

The first two, and seemingly least likely, are numbered 5 and 6 in caucus. Todd McClay and Mark Mitchell are both considered to be rising forces within the party. They’ve both held senior ministerial roles, and Mitchell at least has managed to land a few hits on the government in defence. But they’re probably both best left in the jobs they’ve currently got.

The next major contender is an MP who has risen dramatically up the party ranks, on the back of actually being able to point out weird spending from the government and make it matter. Paul Goldsmith, list MP based in Epsom, has successfully managed to mine the Provincial Growth Fund for stories of profligacy and absurdity. His manner – part forensic investigator, part angry accountant – comes across as the sort of person who would be able to slot in as a finance minister were the government to change suddenly, which surely has to be a consideration with an election in just over a year.

But the final major candidate, and someone who clearly has the ambition and skill for a meaty job, is Judith Collins. She has been turning up in the preferred PM stakes, at times recently even ahead of Bridges. And she has also been by far National’s most successful MP in opposition. Her relentless attacks on Kiwibuild have destroyed the credibility of the policy that arguably carried Labour into government, and have seriously damaged the standing of Phil Twyford. This is a guy that was considered so important, he was given two portfolios utterly crucial to the government’s overall transformational vision. Now drums are beating for him to be rolled in Labour’s own reshuffle. If she tells Bridges that she should take finance, could he deny her, and what would be the consequences if he did?

There’s another, much more outlandish theory about what could happen in the National Party. Perhaps with the departure of Amy Adams, it could give Simon Bridges a face-saving way out of his living nightmare of a leadership. If a case could be made that he’d be better in finance under a Collins leadership, it would also give the party an excuse – they could credibly say that they still rate him highly, he just wasn’t in the right role. That would require Bridges to voluntarily vacate the top job, however; and leaders only very rarely do that.

There’s going to be a wider reshuffle in the National party this afternoon, and one thing is for sure: it won’t be Wairarapa MP Alastair Scott taking the job. He too is standing down, to also bring to an end a tenure that may not have reached the full potential that it could have. If you wanted to look at it cynically, you’d say it’s all lining up neatly for one person at least, departing Air New Zealand CEO Christopher Luxon. He’d been touted as a possibility for the Botany vacancy: suddenly there are deep blue seats springing up everywhere.