Their Government has been buffeted by the realities of coalition management, souring business confidence, and claims they had not delivered the change they promised.
They talked to the Weekend Herald about those, about each other, their mistakes, who would play them in a movie, and what lies ahead as Labour tries to get a second term in power in 2020.
The clock in Prime Minister Jacinda Ardern's meeting room in the Beehive is set five minutes fast.
Grant Robertson points this out, saying it is a cunning tactic to end meetings early.
When the PM says he was not meant to know this, he claims he has "a biorhythmic sense of time".
"It's part of being Minister of Finance."
He is meant to be good with numbers, as her Finance Minister.
The relationship between a Prime Minister and a Finance Minister is the most important relationship in a Government.
She is his boss. They are also good friends.
Q: You've been friends and colleagues for a long time. Grant, what is Jacinda's best attribute?
Robertson: "It is very hard to pick one, but I would say her fierce intellect.
Q: And PM, what is Grant's?
Ardern: He has many, but I would say when you're in a finance role, empathy is incredibly important. He's always focused on the human side of everything, and actually in a portfolio that pulls you constantly to look at a high level, he always thinks about the human side.
Robertson: You should tell that to some of our colleagues, because they don't always feel that when I say no to them.
Q: Which brings us to the next question – what is the most annoying thing about each other?
Robertson: Her fierce intellect. No, she has an attention to detail which can from time to time be an irritant, because she is usually right.
Ardern: [thinks about Robertson's] Ummm.
Robertson: Neatness isn't everything?
Ardern: That's not an irritant, that's amusing. I would say Grant, he's a dog with a bone. If there's something he wants to resolve he will just stick with it until it's resolved and sometimes that can be ... I mean, that's what we need, but his persistence can sometimes be exhausting.
Q: How much do you still have to do with each other outside work?
Robertson: There's something outside of work?
Ardern: In this place, there are definitely blurred lines. You're never just in the supermarket – you're who you are in a supermarket. You're always on.
Robertson: We did manage to watch the Netball World Cup final together as a sleepover at Premier House. But even that, I have a suspicion, was work-related because Jacinda was trying to show me how Premier House needs to be upgraded a bit. It looks a bit like a 1980s motel upstairs.
Ardern: That is actually true.
Robertson: We have had dinner together a few times recently, but that's always a work discussion, that's the reality of it.
Q: And it is true that Grant taught you how to drink?
Ardern: It is true that he was around during the period in which I moved away from being a practising Mormon. He was around at that time, yeah.
Robertson: But she has now far exceeded me in her knowledge of whiskey.
Ardern: That was some time ago, during the last Labour Government. I have very happy memories from that time working in this place.
Q: How do you resolve arguments with each other?
Robertson: The Prime Minister wins.
Ardern: Obviously you can have a long period of time in which you've known each other and that means the starting point in a discussion is that you have respect for the other person's position. So it really will come down to the merits of an individual issue.
Robertson: And in different discussions we are playing different roles. As the Finance Minister my role, quite often, is to be the person who says "well, actually we need to work out how we're paying for that and what we might be trading off against that" and that tends to put me in a particular place in those discussions. But that can shift around.
Ardern: I remember from Opposition doing a lot of work on designing what ultimately became our Families Package. There were things I felt very, very strongly about.
Grant had a few different ideas on elements of that package and in the end there was some compromise there. There was a bit of both in there. I think ultimately that tension means we get a better outcome.
Looking to 2020
Looking ahead to 2020 election – policies, future partners and the question of 'delivery':
Q: Labour is presumably preparing for the next election. How much work is going into preparing new policies and a stock-take of the old policies?
Ardern: We are still the Government, so of course you always have one eye to the future but actually we are very much focused on making sure that for the next 12 months we are continuing to roll out the programme we have.
So I don't want us to be too fixated on election policies because that takes the eye off the ball of what we are here to do now, which is to govern until the end of this term.
Q: But you nonetheless have to inspire the voters to put their faith in you again.
Ardern: Yes of course, but so much of that is inspired by what we do now. People will be looking at our track record over the previous three years to make that judgment as much as they will be looking at what we do next.
For me, this term in office, this is our chance to lay the foundation to say actually we've got to show that we can make good progress on those really gnarly long-term issues.
We won't fix them in three years, and we've always been really open about that. But will people have seen enough progress to say "actually, you deserve the chance to keep going. We know where you are going and why, and we will give you a chance to keep going".
Q: Your tax policy is basically at the greenfields stage, can people expect any surprises there?
Ardern: I'd say that would be a narrow consideration. Obviously we made decisions that were just pragmatic around the capital gains [tax] but we've also at the same time made significant changes to other elements of our tax programme.
Like, for instance, the changes we made to the family tax credit, the work we've been doing on digitisation and modernising the tax system there, working on land banking as well.
There are other elements of that programme that we will keep working on. And, yes, then we will take other options to the election, but that is a matter for the Labour Party.
Q: And will there be any surprises in it?
Robertson: Well, surprise is in the eye of the beholder. But we will put out a tax policy that will be clear on the direction of travel we've got.
Ardern: I think people know what it is that the Labour Party stands for, what our values are.
We cancelled the tax cuts when we came in because we heard a strong message from New Zealanders that actually now wasn't the time. That money went into lifting the incomes of low- and middle-income New Zealanders … [through the Families Package].
People know the values of the Labour Party and so I'd say that most of our policies and ideas don't come as a huge surprise because we've got a framework we work to.
Q: Grant, has the $7.5b surplus given some unrealistic expectations for 2020?
Robertson: I think people have misunderstood what the surplus is. It's the accounts for the year that ended on 31 June 2019. It's therefore not money that is sitting around and available to spend.
In Budget 2019 for the year we are in now, we have put in place a pretty substantial spending programme around health and education and the areas that are important to us.
The surplus that is forecast for the year we are in now is $1.3 billion, and global economic conditions since we made those forecasts have not got better, so I think it is people's understanding of what the surplus is constituted by that is the issue rather than expectations.
Q: You nonetheless have some pressure going on you about income tax cuts in particular because of bracket creep, etc etc. Have you decided what you are going to do there?
Ardern: A lot of the questions have been raised just at the point of the surplus being announced.
Our point is that actually that surplus demonstrates that relative to others in particular we are in a good position.
New Zealand has good, strong economic foundations. It gives us the chance to make decisions in the future, but actually now is not the time for those.
Those are decisions that get made at different parts of the cycle.
Robertson: So the answer is that those decisions haven't been made, and we will continue to take a look at the balance of tax and revenue. I mean, there's no shortage of things to do. We are dealing with a decade of neglect…
Q: I have to power on, sorry.
Ardern: That was rude.
Q: I'm sorry. Time is flying. Prime Minister, you said earlier this year that year one was the year to develop the infrastructure for change …
Ardern: And year two was the year for delivery.
Q: What is year three?
Ardern: The first thing I will say is that in both those cases I absolutely stand by both.
That is exactly what those years have been. And year three is a continuation of that.
When we came in, we outlined the challenges we were facing on basic things, infrastructure, health, our hospitals, not enough school buildings, the inequality for children, our waterways being degraded, a housing crisis.
In all of those areas I am proud of what we have done in 24 months and we have to keep going. Year three is a continuation of that.
If you think that after 24 months suddenly we've resolved all our infrastructure challenges, or that our environmental climate change is suddenly fixed, obviously that won't be the case.
We have to keep going, we have to show that progress and that's ultimately what we will be judged on.
Q: You came up with your new slogan very quickly in 2017, "Let's Do This". If you had to come up with one today, what would it be?
Ardern: Let's Keep Doing This, Let's Keep Going.
This is unfinished. We've always said one of the failings of short electoral cycles is you look at problems in short terms. And actually all the problems we're facing globally around climate change or inequality they now by default require us to plan out to 2050.
Now there are very few democracies that are built around that long-term planning but that's what we've got to do.
Q: Will we get advance notice of your preferred coalition or confidence and supply options ahead of 2020 election?
Ardern: The preferred option is determined by voters. I go out and campaign alongside my colleagues for people to vote for Labour.
My first preference is to gather as many votes as I can for Labour. The rest is up to New Zealand. And then we work with what we get.
Q: If you could form a government just with the Greens and you did not need NZ First, would you form a government with just the Greens?
Ardern: I am not going to run up a lot of hypothetical scenarios with you.
Remembering, of course, I am the leader of the Labour Party, so ultimately my focus will be on getting those votes for the Labour Party to be in the strongest position possible to be able to form a Government again.
Q: Assuming you get back in, would your next Cabinet be very different from the current in terms of the Labour members on it? I know you want to boost the number of women, for example.
Ardern: I do, I do. And actually I think it's incumbent on all leaders to ensure that you have a good path of renewal so those are things that will be on my mind.
But you've asked me whether or not I've thought of the Cabinet in 12 months time. I'm quite focused on making sure the one we've got now is doing its job well.
Q: If you don't get to form the next Government and go back into Opposition, would you stick it out?
Ardern: That's not a hypothetical that I've been entertaining. At all.
Robertson: I know it sounds trite, or cliched, but the truth is we are incredibly focused on the jobs we are doing now.
There is so much work for us to do. Next year we will get into an election campaign and we will run that. And then the result of that will be what it is.
I am hopeful and optimistic that we will be back here, but I'm not considering an alternative until I have to.
Ardern: That's the thing when you've been in Opposition in the past. You just focus on the thing you've been given the privilege of doing. We are in an amazing position right now, to be able to have this opportunity to be in Government.
People don't always see MMP governments like this one. And so, while we are here, we are absolutely going to make the most of that.
Q: There's been a lot of attention on the things there have been issues with, KiwiBuild and light rail. Are you concerned about the impact the focus on those will have on credibility for you in 2020, and how do you stop that narrative taking hold?
Ardern: I think the only way I could describe my response is I am incredibly frustrated that there is this narrative that I actually just think is not true. It is just. Not. True.
And anytime anyone raises that, I challenge them. There are a range of issues that New Zealanders, at the election, prioritised things they wanted us to address. And on every single one of them we've made progress.
On housing, no Government has built as many houses as we have since the 1970s. We've already beaten our targets on state housing. On inequality, the number of children we have lifted out of poverty I am proud of. And on transport, this is an area where ultimately we are going to end up with more investment in public transport and on roading infrastructure than we've seen in years.
And yet there is a narrative that I think is just not true. So I push back on it.
I just have to keep going out and telling the stories of New Zealanders who aren't always getting their time to tell those stories.
I see it in the letters and I see it in the comment[s] of people in the street, and it's not always well-reflected in the commentary.
Robertson: I am looking at a Government with three parties in it that makes decisions every single day, that passes bills, that gets things enacted and it is incredibly frustrating to hear a narrative about delivery that is not correct.
We are delivering. We are making good progress on big, big issues.
Ardern: It does depend who you ask though. I mean, who are we asking? Because I got a letter last week from a man …. His story was that he got a letter about bowel screening. He got a check and as a result his life had been saved.
You ask that person and they will have a very good story and there will be lots of stories out there like that. So, who are we asking? That would be my point.
Q: What is the one mistake you won't make again?
Ardern: Can you ever, ever claim that you will never make a repeat mistake? I'm human.
Maybe the mistake would be trying to claim that I'm not.
I remember the moment I took on this job I said then that I'm going to make mistakes. And I will. I'll keep making mistakes. Every time I'll try and learn from then, absolutely.
But even reflecting back on the last two years, those mistakes people have slated or, in their minds, determined to be mistakes, actually for me have been often the periods where we've actually been really ambitious and had some aspiration and just said "we're not going to accept the status quo" and I'm really unapologetic about that.
Robertson: The mistake I am not going to repeat is I took diaried gym time out of my diary. And I am not going to repeat that mistake.
Q: Is that because you are not going to put it back into your diary?
Robertson: So cynical Claire. Yes, of course I'm going to put it back in.
[Subsequent inquiries with Robertson's office reveal gym time is still in Robertson's diary – he chooses not to notice it].
Ardern: I think for me, this is one that is still building for me, but I think you should never, ever regret the time you put aside to spend with your family.
I think I've made the error, from time to time, of prioritising sometimes things that felt really important in that moment. But actually, yeah, you've got to try and maintain your family and your friendships while you're in this place too. I probably could have done a better job of that.
Robertson: I think you're doing alright.
Ardern: Thanks. We'll see how Neve feels in a few years' time.
Q: And Neve's siblings?
Robertson and Ardern: Good try. Good try, Claire.
Ardern: It's the exclusive she's looking for.
Q: You have two books coming out about you …
Ardern: They are unauthorised. They are definitely not mine.
Robertson: How many books are coming out about me?
Q: You'll feature in her ones. A bit-player. An extra. Who will play each of you in the movie?
Ardern: No one will see that movie. Straight to DVD.
Robertson: I once had someone suggest to me that if I was going to be in a movie I would be played by Robbie Coltrane.
Ardern: Do you want me to pick who would play me? No, no … Elton John.
[Elton John recently said if he was a woman he would like to be Ardern].
Robertson: I like it. Elton John and Robbie Coltrane in a movie about this Government would be perfect. I like that.