Vice President Joe Biden gave a touching and personal speech speaking about Beau Biden, who passed away Saturday, and other family members at Yale University on May 17, 2015. (YouTube/Yale University)

Joe Biden had one final bit of advice, a warning, really, for these very successful students. No matter how accomplished their lives turned out to be, they would not be able to control their fates.

“Reality has a way of intruding,” the vice president told thousands of graduating Yale University students two weeks ago.

Biden spent the next several minutes unfurling a story he had told hundreds, if not thousands, of times before: his improbable 1972 Senate victory, the car crash that took his wife and daughter, the weeks spent coaxing his two young sons toward recovery.

What the crowd didn’t know was that reality had again intruded in the vice president’s life.

Hiding behind a pair of aviator sunglasses that played along with the irreverent traditions of “Yale Class Day,” Biden delivered the speech knowing that his eldest son was dying of cancer — the same son whose injuries in the crash forced Biden in 1973 to take the Senate oath in a hospital room, beside his son’s bed.

In this 1985 photo, Sen. Joe Biden (D-Del.) holds his daughter, Ashley, while taking a re-enacted oath of office from Vice President George Bush during a ceremony on Capitol Hill in Washington as his sons Beau, foreground, and Hunter hold the bible. (Lana Harris/AP)

Beau Biden had already been admitted to Walter Reed National Military Medical Center in Bethesda for what the vice president’s staff would later call “aggressive treatment” of brain cancer.

Joseph Robinette Biden III, 46, the former attorney general of Delaware and a leading candidate for governor in 2016, died Saturday.

In the stoic tradition of Irish Catholicism, the vice president kept his son’s deteriorating condition to a tightknit circle of family, his closest friends, top advisers and President Obama. The president, along with first lady Michelle Obama, visited the Biden home at the Naval Observatory on Sunday to pay their respects to the vice president and his wife, Jill.

In a rare Sunday session scheduled to deal with contentious anti-terrorism laws, senators began with tributes to the Bidens.

Joe Biden’s adult life, spent almost entirely in the public eye, has now been bookended by tragedy.

Before he could formally begin his Senate career, Biden buried his wife, Neilia, and daughter, Naomi. Now, as his vice presidency heads toward its final months, he will bury his oldest son, the heir to the family dynasty who was fast carving his own political identity with seemingly limitless opportunity.

In the past few weeks, the vice president’s closest confidants grew worried about how he could handle another loss.

Ted Kaufman, 76, the former senator and Biden’s longtime Senate chief of staff, returned to work for the vice president in a part-time capacity, mostly just to be at his side during the difficult time. Some worried about whether Biden could deliver the Yale speech, given that the invitation came with a specific request that he tell his personal story.

“We want to hear from you not only because of the positions you’ve held, but also because of your sense of humor and triumphs over tragedy,” Jeremy Hutton and Akinyi Ochieng, student officers of Yale’s Class of 2015, wrote to Biden in November. “You are a shining example of resiliency and compassion for others.”

Rather than skip the address, Biden, 72, turned it into a personal explanation of his career, from sorrow to the Senate, from tragedy to global diplomacy.

Some advisers grew emotional last week when talking about the speech, knowing how close Beau Biden was to death, calling it the crystallization of Joe Biden’s effort to weave his personal beliefs into his political career.

“The most successful and happiest people I’ve known understand that a good life, at its core, is about being personal. It’s about being engaged. It’s about being there for a friend or a colleague when they’re injured or in an accident,” Biden told the Yale crowd, adding: “It all seems to get down to being personal. That’s the stuff that fosters relationships. It’s the only way to breed trust.”

After the 1972 crash, Biden grew sullen, bitter and angry. He credited Sen. Mike Mansfield (D-Mont.), the majority leader at the time, Sen. Edward M. Kennedy (D-Mass.), and other colleagues with coaxing him into serving in the Senate and beginning a daily commute from Wilmington, Del., to Washington, taking Amtrak so he could see his two sons every night.

One day, walking across the Senate floor to meet Mansfield, he grew angry as he listened to the archconservative Jesse Helms (R-N.C.) excoriate a proposed bill to help people with disabilities. Sensing Biden’s temper, Mansfield sat the freshman senator down and told him how Helms and his wife had adopted a teenage boy who couldn’t walk.

“Joe, it’s always appropriate to question another man’s judgment, but never appropriate to question his motives,” Mansfield told Biden, the vice president recalled two weeks ago.

By the mid-1990s, taking over as the top Democrat on the Foreign Relations Committee, Biden forged a bond with Helms, the irascible chairman, that produced a string of legislation that became the hallmark of his career, including a chemical weapons treaty and funding to fight AIDS in Africa.

That personal side of Biden has also proven to be a point of weakness. He is prone to saying things at the wrong time or in the wrong place, a tendency that has frustrated a White House that has tried to lived up to its mantra of “No Drama Obama.”

Biden once called himself “the White House optimist,” always looking for the bright side no matter how stark the situation. The Onion, the satirical online news site, turned the vice president into a punch line associated with muscle cars and tough-guy antics, and the White House social media team crafted a regular feature, “Being Biden,” that played into this meme.

That lighthearted, sometimes joking persona, along with his age, has made another Biden bid for the White House unlikely in the minds of many. Hillary Rodham Clinton — one of the more disciplined politicians of the era — has solidified her place as the 2016 Democratic front-runner. Officially, Biden has said a decision will come this summer.

Some Obama critics have said that he needed to be a little more like Biden, suggesting that the president’s impersonal nature has hurt his standing on Capitol Hill and that had he been more like Biden he would have accomplished more.

But those closest to Biden credit Obama for picking Biden as his vice president, seeing it as a sign that the president knew his own shortcomings and understood Biden’s connection to Capitol Hill.

After 36 years in the Senate, Biden often became the president’s bridge to Democrats and Republicans in Congress. From late 2010 through New Year’s Eve 2012, Biden was the point man for fiscal negotiations, usually with Sen. Mitch McConnell (R-Ky.), and by Obama’s second inauguration, Biden was riding as high as ever. During the inaugural parade he ran along Pennsylvania Avenue, doing impromptu TV interviews, high-fiving strangers and posing for pictures. In July 2013, GQ did an extensive profile under this headline: “Have you heard the one about President Joe Biden? That’s no joke.”

A month later, reality intruded again.

Beau Biden was diagnosed with brain cancer in August 2013 and admitted to MD Anderson Cancer Center in Houston, where surgery was performed. He was given a clean bill of health months later.

Joe Biden never hid the fact that Beau was a special member of the family. “I really do admire Beau more than anyone I know. He’s a decent, honorable man,” then-Sen. Biden told Roll Call in 2006 during his son’s successful 2006 race for attorney general.

In August 2008, he chose Beau to introduce him before accepting the vice presidential nomination at the Democratic National Convention. His son told the story of his mother and sister dying in the crash; how his father cared for him and his younger brother, Hunter; how his father found love again and overcame despair.

“I have something to ask of you,” Beau Biden, who was departing for a tour of duty in Iraq with the Delaware Army National Guard, said to the crowd. “Be there for my dad like he was for me.”

Two weeks before his son’s death, the vice president brought the Yale crowd to complete silence when he said that his mother’s words on the day of his first wife’s death — “something good will come if you look hard enough” — had come true.

“The incredible bond I have with my children is the gift I’m not sure I would have had, had I not been through what I went through,” Biden said, his sunglasses still in place.

He went home every night on Amtrak because he found solace mostly through his children, the need to hear their stories before the words disappeared.

“I came to realize that a child can hold an important thought, something they want to say to their mom and dad, maybe 12 or 14 hours, and then it’s gone,” Biden said.

“And when it’s gone, it’s gone.”