It lasted only a short time, and it hardly eclipsed the bitterness of partisan politics that has consumed the country. But for nearly five minutes on Wednesday morning, Joe Biden and Meghan McCain shared an emotional exchange about the aggressive form of brain cancer that has affected both of their families.
The clip from “The View,” on which Mr. Biden, the former United States vice president, was a guest, drew a powerful and heartfelt outpouring online from viewers.
Ms. McCain, a Republican who co-hosts the morning talk show, told Mr. Biden, a Democrat, that she “couldn’t get through” his new book, “Promise Me, Dad,” about his son Beau’s battle with the disease.
Ms. McCain’s father, the Republican Senator John McCain of Arizona, has glioblastoma, which Beau died of in 2015.
“I think about Beau almost every day, and I was told,” she said and paused, choking up, “that it doesn’t get easier but that you cultivate the tools to work with this and live with this. I know you and your family have been through tragedy that I couldn’t conceive of. What would you tell people — —”
Mr. Biden, 75, stopped her, took a seat next to her, grasped her hand and said to her directly: “One of the things that gave Beau courage, my word, was John.”
“You may remember when you were a little kid, your dad took care of my Beau,” he said to her, while Ms. McCain, 33, wiped away tears. “And Beau talked about your dad’s courage — not about illness, but about his courage.” Mr. McCain was the Republican presidential nominee in 2008, the year Barack Obama was elected president and Mr. Biden vice president.
While the brief conversation won’t alter the big policy debates of the day — Mr. Biden and Mr. McCain have taken different, and often opposite, stances on major points of contention — it momentarily bridged the aisle, prompting people on social media to share how deeply they were moved.
One woman responded on Twitter: “Watching my dad lose his battle with cancer was the most heart-wrenching and emotionally (and physically) exhausting thing I have ever endured. This world needs more compassion, love, and care like this.”
On the show, Mr. Biden moved to comfort Ms. McCain by sharing information about new treatment for glioblastoma. “If anybody can make it,” he told Ms. McCain, it’s your father.
“Her dad is one of my best friends,” he said, to applause from the crowd. “Her dad goes after me, hammer and tong. We’re like two brothers who were somehow raised by different fathers or something, because of our points of view.”
Mr. Biden and Mr. McCain accepted a civility award together in 2016 from Allegheny College, a liberal arts school in Meadville, Pa., for their enduring friendship.
Mr. McCain’s diagnosis was disclosed in July, the month he went on to give a middle-of-the-night thumbs-down that killed a Republican effort to repeal the Affordable Care Act. In September, he announced that he would oppose another Republican health care proposal, which helped doom it.
Mr. Biden told Ms. McCain and the audience that even when Mr. McCain got angry with him and told him to get off the Democratic ticket in 2008, he knew that Mr. McCain would be there for him if he needed help. “I know if I picked up the phone tonight and called John McCain,” Mr. Biden said, “he’d get on a plane and come, and I would for him, too.”
What Beau insisted on, he said, is “you’ve got to maintain hope.”
“We got to just keep moving like this is going to happen,” he said. “I swear, guys, we are going to beat this damned disease. We really are.”
After the segment, Ms. McCain wrote on Twitter: “There are no words I have to convey my immense gratitude to @JoeBiden and his family – your strength, hope and fortitude are an inspiration to me and so many others daily. Thank you for your kindness today and sharing your story with us @TheView.”
Mr. McCain echoed his daughter’s sentiment on Twitter: “Thank you @JoeBiden & the entire Biden family for serving as an example & source of strength for my own family.”