Study examines how health issues affected four former prime ministers' performance

Four of New Zealand's former prime ministers were so sick two died in office, one shortly after leaving, and the last drank so heavily at critical times that on one bender he called a snap election which his party lost.

Now a New Zealand Medical Journal article is calling for further research into health impaired former PMs and whether leaders should undergo medical assessments before and during office.

It also highlighted concerns with supporters who enabled their leader to remain in office while physically incapable of the job by hiding the true extent of their impairment.

The article, released on Friday and written by Otago University Professor Nick Wilson, researcher Dr John Horrocks and George Thomson, discusses the growing international concern around impaired leaders, especially in a world of heightened geopolitical instability.

Horrocks noted former United States president Joe Biden during his election campaign debate against opponent Donald Trump last year when Biden shocked viewers with poor skills and slurring words.

The article referred to previous research that concluded: "Who ends up in office plays a critical role in determining when and why countries go to war".

It examined the four New Zealand cases and called for further research into other impaired former prime ministers, and a discussion around possible safeguarding against such situations including requiring independent medical assessments.

"Tensions between privacy of health information and protection of government decision-making need to be resolved, but it could reduce the chance that a country might have political leaders with diminished understanding of their own limitations," the article said.

The four case studies highlighted leaders with diminished capacity leading to reckless decision-making.

The four prime ministers were Sir Joseph Ward, who died at 74 just six weeks after leaving office in May 1930, Michael Joseph Savage, who died in office on 27 March 1940 at age 68, Norman Kirk who was 51 when he died in office in August 1974 and Sir Robert Muldoon, who was on various medications and whose drinking contributed to the demise of his leadership in 1984.

"All of these figures were reluctant to accept limitations to their authority, despite urgings from associates who considered them no longer able to make sound decisions or too ill to carry out their work."

Ward's second term as PM from December 1928 was dogged by serious errors, over-promising, physical frailty and poor health, according to the article - which sourced the history from biographies.

"Apart from these demonstrations of Ward's failing capacity to make good decisions, his declining health meant that more and more of his work had to be delegated.

"Important public engagements had to be passed onto ministers, and his own family were closely involved with his support."

In October 1929 Ward had a stroke.

Two months later on 28 December 1929 police shots killed 11 in Western Samoa, which was administered by New Zealand at the time, but Ward was in bed sick and his whole ministry was absent on holiday.

The article said the slow response from Ward's government, which eventually sent a ship to deal with the emergency on 31 December, demonstrated the danger of impaired leadership with Ward himself initially considering suppressing the bad news.

During the following five months he spent much of his remaining time in office convalescing in Rotorua or at his home, with one photo from the time showing him in a wheelchair in his garden.

Head of the first Labour Government from 1935 to 1940, Savage died of colon cancer while in office after deferring essential surgery to campaign in 1938.

"As his sickness progressed, his behaviour was marked by increasingly erratic and violent outbursts when challenged by members of the Labour caucus."

The article said he grew increasingly rattled by criticism and threatened to knock off the head of one commentator, and implied he would fight members of his own caucus.

At the same time the public was constantly reassured about the 68-year-old's health including three weeks before he died in office, by associates who stated in the Labour Party paper, "Mr Savage is not only fit and looking very fit, but in daily consultation with his Ministers".

Labour leader Kirk's secrecy about his health problems, including diabetes and a mini-stroke in India in December 1973 that left him temporarily paralysed, left little time to prepare a successor after his sudden death in office in August 1974.

The 51-year-old had only been prime minister less than two years but during that time he had collapsed several times, once while speaking in the House and another when he passed out in his room in Parliament.

"His colleagues smuggled him out of the House and took him home."

In April 1974 while on a fishing trip in the Bay of Islands, Kirk could hardly walk for pain in his legs, was struggling to breathe and was coughing up blood.

An operation to treat varicose veins left him with an embolism that caused pleurisy.

Kirk swore the doctor to secrecy and the official bulletin reported he had the flu.

By the time Kirk was days away from death in August that year, with an enlarged liver and heart failure, he was still insisting no one was to know how sick he was.

Muldoon had been a popular and powerful National Party politician who became prime minister in 1975, but whose notoriously abrasive behaviour was also impacted by excessive alcohol use, the article said.

"For example, during a late-night session on 4 November 1976, Muldoon, described as 'liquored up' by Social Credit MP Bruce Beetham, accused Labour MP Colin Moyle of being 'picked up by the police for homosexual activity'.

"This accusation and its messy aftermath, which included a commission of inquiry, ultimately resulted in Moyle's resignation before the end of the year."

The article said Muldoon was drinking when he called a snap election, otherwise dubbed the "Schnapps Election", in June 1984 following a tense meeting with MP Marilyn Waring concerning her opposition to the government's policies for women.

Waring described Muldoon as "pouring himself brandies during a foul-mouthed harangue", the article said, after which he called a caucus meeting to endorse his decision for an early election.

The article said at 1am the prime minister announced the new date through slurred speech on national television and later was so insistent he could drive himself home that government whip Don McKinnon had to arrange for someone to go to the Beehive garage and let down a tyre on his car.

Muldoon, who at the time was on three medications for diabetes, hypertension and a muscle relaxant for chronic back pain, lost the election.

Horrocks, said all of the PMs displayed one or more features of failing political leadership including a belief their leadership was superior and no-one else could do the job, the need for secrecy or denial, being enabled by supporters to hide their impairments, making poor decisions, and being absent from office.

He said it would be hard and not necessarily correct to install mandatory medical assessments and upper age limits on prime ministers and he said the public would rely on the media to scrutinise the behaviour of leaders.

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