The person who has undoubtedly had the biggest impact on John Key is his mother. Ruth Key was a woman with a stoic capacity to pick up her life and start again - once as a Jewish refugee, a second time as the widowed mother of three.
Tough yet compassionate, she loved her three children and gave them the things she was robbed of - a homeland and stability.
Born Ruth Lazar in Vienna, Austria, in November 1922, she was the youngest child of Max, a successful trader with his own leather merchant business, and Margarethe (nee Karpeles).
With her brother Herbert, 21 months older, Ruth was brought up a non-orthodox Jew. In 1938 when Hitler annexed Austria, Jews faced the choice of escape or death.
A schoolgirl at the time, Ruth must have been terrified. Her father had died of cancer, and now the Holocaust was upon them.
In desperation, Ruth's aunt, Lottie Karpeles, fled to Britain and paid a British soldier to marry her. It was a marriage of convenience - they exchanged vows, walked out of the registry office and never saw each other again. But the marriage enabled Lottie to secure British visas to help her family escape.
Ruth and Herbert arrived in Britain in February 1939. Her grandmother made it out too, as did her mother, Margarethe.
Lottie's act of selflessness and resourcefulness was something Ruth never forgot. "She was always grateful and she knew that that was the only way she got out [of Austria]," says Ruth's younger daughter, Sue.
During her first months in Britain, the teenage Ruth required grants from the Jewish Aid Committee. She eventually found work as a milliner, then signed up with the ATS, the women's branch of the British Army.
In 1948, she was introduced to the divorced George Key through her Aunt Lottie, and the couple married. They moved to New Zealand, but by 1969 Ruth was on her own with three children when George died of a heart attack.
Ruth's reaction was instinctive. She was a woman who had fled Nazi occupation and started a new life in England, then boarded a ship with her husband and young daughter bound for halfway around the world. Facing more turmoil, her reaction was to pack up again.
But she had an extraordinary ability to move on. Her attention was on what was best for the children, says her older daughter, Liz.
"She had responsibilities and we were everything to Mum. For her it wasn't a matter of saying, 'Well, gosh, what am I going to do?' She just got up and did it."
One of the things Ruth left behind, at least for the time being, was her religion. She attended synagogue with Liz in Auckland, but once the family moved to Christchurch, she put that part of her life on hold. It was not until the children had left home that she began practising her faith again.
Sue says she believes Ruth had decided religion was one of the things she had to leave in the past while she concentrated on bringing up the children. "But as you age you go back to your roots and so she returned to the synagogue."
Ruth did not practise while the children were around, but she left them in no doubt about their Jewish roots.
"We would not have been in the predicament we were if we weren't Jewish. Mum would never have had to escape from Europe, we would have had a family, and we would have had stuff from the past," says Sue.
On a trip to Austria about four years ago, Liz realised how much her mother had been a product of her homeland.
"The women were just like my mother, sharp and demanding, honest and factual. There was no small talk."
Gwendoline Howard, a neighbour from their time in Hollyford Ave, Christchurch, came to know Ruth well. "She and my husband used to sit at the end of my table smoking," says Howard. "She'd always want to know what was going on - she never missed a beat. She'd lift up the lids of your pots to see what you were having for tea."
Such nosiness doesn't surprise her daughters. "Mum knew everything about everybody," says Sue. "If somebody came and Mum had seen them with a girl, she'd say, 'Is that your girlfriend? Are you sleeping with her?' We'd be going bright red, saying, 'Mum!' And people would say, 'Oh, no, she's only really interested'."
Through the upheaval and sorrow of Ruth's life, her children and grandchildren were a joy. She loved them deeply and made it her life's work to ensure they had every opportunity.
About 10 years ago, after the break-up of her first marriage, Sue spent a lot of time thinking about the sacrifices her mother had made. Instead of switching back to her maiden name, Key, she decided she would adopt her mother's maiden name, Lazar.
"I made a conscious decision: it was Mum who had done all the raising and I wanted to take her name," says Sue. "When I look back I think it was such a compliment to Mum and I'm glad I did it before she got sick and before she died so that she knew."
Ruth Key died in May 2000, aged 77, struck down by pneumonia after several years of ill health, including Alzheimers.
On election night this year, no matter the result, John Key will be surrounded by his family - his wife and children, his two sisters and their families. But they will all spare a thought for the woman who made it possible.
"For John, if he does make Prime Minister, part of it will be tinged with sadness that she's not there," says Sue. "That day he will think, 'I wish Mum could have seen this'."