In December 1972, not long after winning a U.S. Senate seat from one of Delaware’s oldest political hands, Joe Biden began traveling to Washington to introduce himself around town.

Strapping and handsome, Biden had just turned 30, the minimum age to become a senator. Now, almost 50 years later, he is about to become the nation’s oldest president at 78. Back then, he was the sixth-youngest senator in U.S. history, according to the Senate website.

Worried people would think he was a congressional page, Biden stuck out his right hand to everyone he encountered, even elevator operators.

“Hi, I’m Joe Biden,” he’d say, “the new senator from Delaware.”

Biden’s wife, Neilia, usually accompanied him on these trips, sometimes with their three young children. She and his sister, Valerie, had run his campaign and got Joe, as friendly then as the world knows now, into homes across the tiny state for coffee with voters.

The week before Christmas, as Biden set off on another trip to Washington, Neilia stayed home, getting the house ready for the holidays. That afternoon, Biden and Valerie sat working in an office loaned to them by Sen. Robert Byrd. The phone rang. Valerie took the call.

“There’s been a slight accident,” she told Biden, as he later recalled in his memoir. “Nothing to be worried about, but we ought to go home.”

The way she said it told a different story.

“She’s dead,” he said, “isn’t she?”

She was, along with their 1-year-old daughter, Naomi.

They had been killed in a car crash that left their two sons, Beau, 3, and Hunter, 2, badly injured. For any father and husband, this would be a crushing, defining moment in life, but for Biden, it also set off an extraordinary period of days that would forever shape his political future — and the country’s.

Sitting vigil by his sons’ bedsides, Biden was wrecked, and at times, he needed to be sedated, according to political reporter Jules Witcover’s biography, “Joe Biden: A Life of Trial and Redemption.”

“I felt trapped in a constant twilight of vertigo,” Biden wrote in his memoir, “like in the dream when you’re suddenly falling ... only I was constantly falling.”

There would be no political career, he decided. From the hospital, he notified Senate Majority Leader Mike Mansfield (D-Mont.) that he would not be accepting the seat he won. There seemed to be no talking him out of it, either. Mansfield called the hospital daily to convince Biden otherwise, according to Witcover.

Biden kept saying no. But Valerie, his sister, looked for openings to convince him. She moved in with him, gently prodding him to think ahead, not behind. The family could help with the boys. He didn’t need to choose between raising them and being a senator, friends and family told him.

“Once he realized that his priority was in being a good father and then a good senator, he could achieve that,” she told Witcover. “He could achieve one without doing harm to the other, then he was okay with it.”

Biden decided to move forward and accept the oath of office, but the machinery of Washington would need to come to him — and the hospital in Wilmington, Del. — to make it official.

In early January 1973, Francis R. Valeo, the secretary of the Senate, and Dorothy Scott, his administrative assistant, traveled to Wilmington to administer the oath of office in the hospital’s chapel.

“Beau was still bedridden with his fractured left leg in traction, but the bed and boy were wheeled into the room,” Witcover wrote. “His brother, Hunter, released from the hospital after treatment for a slight skull fracture, was brought into the room by his grandfather, Neilia’s father, and sat on Beau’s bed to watch the ceremony.”

CBS News White House reporter Dan Rather was filling in as anchor that evening.

“The story had a little bit of everything,” Rather said in a recent interview. “The tragedy of his wife and young daughter, the swearing-in at the hospital. Of course, there was his age. It was pretty extraordinary.”

But it was Biden’s short speech that Rather remembered most.

“I make this one promise,” Biden said. “If in six months or so there’s a conflict between my being a good father and being a good senator, which I hope will not occur,” then he would inform the governor that he would give up his seat.

“We can always get another senator,” Biden said, “but they can’t get another father.”

The rest, of course, is political and railway history. Biden famously took Amtrak back and forth to Washington every day so he could be at home in the evenings for his sons. Biden is reportedly considering taking an Amtrak train to his inauguration on Jan. 20.

Just as he has done recently, Biden had promised to be a senator for all parties, not just for his own.

“I won’t be toeing any party line or listening to the majority leader when I don’t agree,” he told a reporter on election night, according to Witcover’s book. “I’m in a unique position. I’m 30 years old, the youngest senator down there. I might be able to sit there for another forty years if I’m a good boy and play my cards right.”

Biden had reached his ultimate goal, he told the reporter.

But many political observers, including Rather, thought that wasn’t exactly true.

The day Biden was sworn in, Rather called several senators.

“What do you think about this new guy, Biden?” he asked.

Their answers were easy to remember all these years later.

“Each of them,” Rather recalled, “told me that you’re probably looking at a future president of the United States.”

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