Washington (AFP) - One of the youngest senators in US history, vice president for eight years and now frontrunner for the 2020 Democratic presidential nomination -- Joe Biden has had a storied career.
But Biden's life in politics has also been intertwined with personal tragedy, in some ways defining him in the public eye. And now his troubled youngest son has been thrust into the glare of a bitter White House race.
Biden's first wife, Neilia Hunter, and one-year-old daughter, Naomi, died in a car crash in 1972 while Christmas shopping, just weeks after Biden had defied the odds and won election to the Senate from the tiny eastern state of Delaware.
The accident left his two sons, Joseph "Beau" Biden III, 4, and Robert Hunter Biden, 2, badly injured, and the 30-year-old Biden was sworn into the Senate beside his sons' hospital beds.
While serving in the Senate, Biden would commute 120 miles (200 kilometers) by train every day from Washington to his home in Wilmington, Delaware, a practice he would continue during his 26 years in Congress.
Biden met his second wife, Jill Jacobs, a schoolteacher from Pennsylvania, in 1975 and they married two years later.
She helped raise his boys and they have a daughter, Ashley, born in 1981.
Both boys recovered from their injuries and Beau eventually followed his father into politics, becoming the attorney general of Delaware and contemplating a run for state governor before dying of brain cancer in 2015 at the age of 46.
Joe Biden was serving as vice president to Barack Obama at the time and he renounced a presidential bid in 2016 in part because he was still grieving over his son's death.
Biden recounted Beau's agonizing final year in a book, "Promise Me, Dad: A Year of Hope, Hardship, and Purpose."
- Hunter Biden -
The 76-year-old Biden frequently references his painful family history on the campaign trail, particularly the loss of his first wife and the struggle to raise two young boys on his own.
Biden's younger son, Hunter, earned a law degree from Yale University and has had a checkered career as a lawyer and lobbyist.
Hunter has struggled with alcohol and drug addiction, a battle he candidly recounted in a profile published in The New Yorker in July. It has included several stints in rehab.
Following his brother Beau's death, Hunter became briefly romantically involved with Beau's widow, Hallie Olivere, and his wife of nearly 25 years, Kathleen Buhle, filed for divorce.
It is Hunter's business ventures in China and Ukraine that have put him in the spotlight of the 2020 presidential race and at the center of the latest political scandal swirling around President Donald Trump.
Trump has been accused of pressuring Ukraine's new President Volodymyr Zelensky to investigate Hunter's business dealings in Ukraine, where he served on the board of the Ukrainian gas company Burisma Holdings while his father was vice president.
Trump reportedly pressed Zelensky about eight times during a July 25 telephone call to investigate possible corruption involving Burisma and Hunter, who has not been officially accused of any wrongdoing.
The phone call in question came to light after an unknown whistleblower sounded the alarm and filed a complaint with the inspector general of the US intelligence community.
Joe Biden said over the weekend that Trump's actions appeared to be "an overwhelming abuse of power," and Democrats in Congress have ramped up calls to impeach the Republican president.
Trump shrugged off the impeachment threats on Monday, said he had done nothing wrong and doubled down on his attacks on the Bidens.
"What Biden did is a disgrace. What his son did is a disgrace. The son took money from Ukraine and from China," Trump said without providing any evidence.
Biden for his part said he has "never spoken" to Hunter about his overseas business dealings and that those who have looked into them have "said there's nothing there."
"Trump is doing this because he knows I'll beat him like a drum and using abuse of power and every element of the presidency to try to do something to smear me," Biden said.