Mr Biden and sons Hunter, left, and Beau walk in the Inaugural Parade in January 2009 in Washington. AFP / Getty Images
Joe Biden speaks with his bedridden son, Beau, before he was sworn in as the US senator from Delaware in January 1973. Mr Biden's first wife and daughter were killed in the car accident that injured his two sons. AP
Mr Biden on a trip to China while he was the US Senate Foreign Relations Committee chairman in 2001. AFP
Mr Biden, then a senator, tours ground zero with fellow Senate members Ted Kennedy and Barbara Mikulski. AFP
Mr Biden meets Rafic Hariri, the assassinated prime minister of Lebanon, in April 2002 in Washington. AFP
Mr Biden meets late Israeli prime minister Ariel Sharon in June 2002. AFP
Mr Biden meets Ibrahim Jaafari, who was Iraqi prime minister at the time, in Baghdad in May 2005. AFP
Mr Biden and his wife Jill celebrating their son Beau's election as attorney general of Delaware. AP
Mr Biden in Ramadi, Iraq, in 2007. AFP
Mr Biden squares off against Sarah Palin during the vice presidential debate at Washington University in St Louis, Missouri, in October 2008. Reuters
The Bidens and Barack and Michelle Obama arrive for an election night party in Chicago, Illinois, in November 2008. AFP
Mr Biden meets Jalal Talabani, the Iraqi president at the time, in Baghdad in January 2009. AFP
Mr Biden and sons Hunter, left, and Beau walk in the Inaugural Parade in January 2009 in Washington. AFP / Getty Images
Joe Biden speaks with his bedridden son, Beau, before he was sworn in as the US senator from Delaware in January 1973. Mr Biden's first wife and daughter were killed in the car accident that injured his two sons. AP
Mr Biden on a trip to China while he was the US Senate Foreign Relations Committee chairman in 2001. AFP
Mr Biden, then a senator, tours ground zero with fellow Senate members Ted Kennedy and Barbara Mikulski. AFP
Mr Biden meets Rafic Hariri, the assassinated prime minister of Lebanon, in April 2002 in Washington. AFP
Mr Biden meets late Israeli prime minister Ariel Sharon in June 2002. AFP
Mr Biden meets Ibrahim Jaafari, who was Iraqi prime minister at the time, in Baghdad in May 2005. AFP
Mr Biden and his wife Jill celebrating their son Beau's election as attorney general of Delaware. AP
Mr Biden in Ramadi, Iraq, in 2007. AFP
Mr Biden squares off against Sarah Palin during the vice presidential debate at Washington University in St Louis, Missouri, in October 2008. Reuters
The Bidens and Barack and Michelle Obama arrive for an election night party in Chicago, Illinois, in November 2008. AFP
Mr Biden meets Jalal Talabani, the Iraqi president at the time, in Baghdad in January 2009. AFP
Mr Biden and sons Hunter, left, and Beau walk in the Inaugural Parade in January 2009 in Washington. AFP / Getty Images