For every politician, events of their past influence their political career and the person they are.
But for Joe Biden, the story is particularly poignant.
The 77-year-old was just embarking on his journey in politics when his life was changed irreparably by the death of his wife and daughter.
That moment in 1972 would not only change the presidential hopeful’s personal life, but would influence the way he conducts himself on the public stage.
Who was Joe Biden’s first wife?
Following his degree, Biden moved to Syracuse to attend law school and the couple married in 1966 while he was still studying there.
After his graduation, they moved to Wilmington in Delaware where he practised law and won a seat on New Castle County Council in 1970.
The couple went on to have three children - sons Beau and Hunter and daughter Naomi, who was nicknamed Amy.
In 1972, Biden ran for a Delaware seat in the US senate, with his wife playing a key role in his campaign.
They succeeded and, in November that year Biden, then 30, won the seat from Republican incumbent J Caleb Boggs.
How did Joe Biden’s wife Neilia and daughter Naomi die?
Just weeks after he was elected, while Biden was in Washington DC interviewing people to work in his new office, he received a phone call that would change his life forever.
While out Christmas shopping, Biden received a phone call telling him Neilia and Naomi - who was just 13 months old - had been killed in a car accident. Hunter and Beau, who were four and three years old, were in critical condition.
Speaking about the tragedy in a speech at Yale in 2015, Biden described the moment he took that call.
“Six weeks after my election, my whole world was altered forever,” he said. “While I was in Washington hiring staff, I got a phone call. My wife and three children were Christmas shopping, a tractor trailer broadsided them and killed my wife and killed my daughter. And they weren’t sure that my sons would live.”
During a campaign speech in 2008, Biden also spoke openly about seeing his children in hospital after the crash.
How did the death of his wife and daughter affect Joe Biden’s career?
The death of Neilia and Naomi would prove to shape the direction of Biden’s political career.
His senate swearing-in took place at his sons’ bedside in hospital and he went on to commute daily from Washington to Delaware to spend time with his sons, gaining the nickname ‘Amtrak Joe’.
During his Yale speech, he said: “I began to commute thinking I was only going to stay a little while — four hours a day, every day — from Washington to Wilmington, which I’ve done for over 37 years.
“I did it because I wanted to be able to kiss them goodnight and kiss them in the morning the next day… But looking back on it, the truth be told, the real reason I went home every night was that I needed my children more than they needed me.”
Biden described his focus on his sons as his “redemption”. Beau went on to die of a brain tumour in 2015 in another tragedy to hit the family.
In his 2017 book “Promise Me, Dad”, Biden wrote that “the pain ... seemed unbearable in the beginning, and it took me a long time to heal, but I did survive the punishing ordeal. I made it through, with a lot of support, and reconstructed my life and my family”.
The Democrat, who went on to marry current wife Jill in 1977, has described how his own experiences have helped him connect with voters who have been through similar tragedy.
In an interview with MSNBC, he said: "You'd be amazed at the number of people who come up to me. I mean hundreds of people over time. They'll throw their arms around me, men and women, and say, 'I just lost my son, I just lost my father, I just lost my wife.' And all they want to know is that you're going to make it.”