One cold December weekend a month before his death, 66-year-old Hubert Humphrey was at last driven down the tree-lined lane leading to Camp David. Though Humphrey had dedicated over 30 years to public service — from Minneapolis mayor to the vice presidency — it wasn’t until President Jimmy Carter’s time in office that Humphrey received the invitation he’d long sought.

“[H]e was very effusive in his thanks, telling me over and over how great a favor I had done for him,” President Carter later remarked. “It was the greatest favor I ever did for myself.”

The pair spent much of the weekend swapping stories by the fireplace at Aspen Lodge, one of Camp David’s most comfortable retreat spaces. The lodge’s large, light-filled windows provided some of the best views, and at this late juncture in Humphrey’s life, the windows seemed important to him.

“He’s begun to appreciate the small things:” Carter wrote in his diary, “how birds feed and the color of leaves, the sound of music … .”

Here was a man who had been an early and tireless advocate for civil rights, whose commitment to the Voting Rights Act, the War on Poverty and establishing the Peace Corps would collectively serve as a north star for America’s future. Yet even in his final weeks, as his bladder cancer worsened, Humphrey’s lifelong yearning to serve his country never dissipated.

“Hubert seemed to be in good spirits,” Carter observed in his diary. “The Happy Warrior,” as he’d long been known, seemed glad to be spending one of his last weekends with a man he admired in a place he’d never been.

Indeed, Camp David was teeming with history, which Humphrey appreciated — from FDR and Churchill’s fishing expedition to many of Kennedy’s Cuban missile crisis meetings. It was a place for presidential play but also for serious business.

And for one frigid and windy weekend in December, it was also a place to say goodbye.

As the fire crackled, Humphrey attempted to offer the president some parting advice.

(No one had ever accused Hubert Humphrey of being short of words, and he wouldn’t start now.)

Humphrey advised Carter not to be overly concerned by the daily criticisms. Instead, commit yourself to a policy, ensure it is well-advised, and stay the course.

Also, Humphrey added, “ignore the harpings of the press.”

It was the advice Carter most needed to hear. A reminder that he could not please everyone (or, some days, anyone) but that one’s principles could always outlast a news cycle.

Life is short, but policies are long.

Legend has it that Hubert and Jimmy stayed up late that Saturday night, watching movies. On Sunday morning, they rose and went to church. On Jan. 16, when called upon to deliver Humphrey’s eulogy, President Carter revealed more details about their weekend at Camp David. How they had talked about pain — both “the physical pain that I could see that he was bearing” as well as “the pain of losing a political campaign.”

Though Carter wouldn’t know the full extent of the pain of losing a presidential election for another three years, perhaps Humphrey had given him a glimpse of that future.

Carter deemed it “one of the most enjoyable and interesting weekends I’ve ever spent,” yet much about that weekend is now lost to history.

With Carter’s passing, we lost not only a man but one of the longest links in America’s long chain of our past.

“This is a sad day for me,” Carter wrote in his diary on the day Humphrey died.

Upon learning of Carter’s death, I wrote much the same in my own diary. How often I’ve dreamed of being a fly on the wall of the Aspen Lodge for those two days in December. How much I could’ve learned had I been there.

In the last days of his life, Hubert Humphrey taught Jimmy Carter a lesson from which we can all benefit: Life is short, but legacies are long.

B.J. Hollars, of Eau Claire, Wis., is a writer, professor and author of “Wisconsin for Kennedy: The Primary That Launched a President and Changed The Course of History.”