Palmer, a constitutional lawyer, describes Prime Minister Robert Muldoon as running an elected dictatorship between 1975 and 1984. It's a big claim. Sometimes it's the small stories that illustrate the point. Palmer recalls that when he became deputy Labour leader to David Lange in 1983 they ordered a couch for their offices but the request was denied - not by some bureaucrat but by Muldoon himself. The Prime Minister would decide the level of comfort to which his opponents could become accustomed.
Palmer would change all that. He established the Parliamentary Services Commission, an independent body to provide services to MPs. He introduced regular sitting hours to Parliament. Who cares? Well, the Official Information Act 1982 - supposed to give greater transparency to government actions - was passed just before 4.30am. A lot of legislation - from the important to the self-serving - was passed in the dead of night, when some MPs were asleep, drunk or insanely tired. That is if Parliament sat at all. When Palmer first arrived Parliament would sit for four or five months a year. The rest of the time, well, the Prime Minister ran the country.
Ultimately, of course, Palmer would get his chance to run the country too. He was Prime Minister for 13 months sandwiched between David Lange and Mike Moore, who a desperate Labour party turned to just two months before the 1990 election in a bid to save the furniture.
Doing a series like this and spending hours with the former Prime Ministers you get the chance to ask the simple - even the stupid - questions as well as getting down into the detail. So what was it like to run the country? What is it like to be Prime Minister? "I found being the leader a nuisance," Palmer told us. You found being the Prime Minister of New Zealand a nuisance? "I did."
He outlines his full reasons for this in the interview but essentially he saw being Prime Minister as a superficial job, part of a celebrity culture which pandered to the media (which he is also scathing of).
If that was his view of political leadership circa 1990 what does he think about it now in the age of Twitter, daily opinion polling, fake news and Donald Trump? You certainly don't die wondering with Palmer. We talk about his concerns for our democracy today and his role in Rogernomics in the past. Did he think the privatisations and deregulation were radical, neo-liberal ideas or just conventional economics? Did Labour MPs even know what Roger Douglas was going to unleash? Part of the joy of this series is that we could put those same questions to all the key players, so over five weeks you'll be able to get a sense of where these key figures agree on what they did and why and where history is still very much disputed.
Palmer also had a much more critical role in making New Zealand nuclear free than is commonly acknowledged. It was him - not David Lange - who turned back the US warship, the USS Buchanan, at the critical moment; Lange wasn't even in the country.
How leaders make those kinds of calls, how the decision process works and how power is wielded: that was at the heart of our mission when we researched and interviewed the five Prime Ministers for this series.
Palmer is an essential voice on what it means to exercise power - precisely because he never wanted it and remains highly sceptical of those who do.