Kamala Harris tears up as she recalls her mother's cancer diagnosis

The first voice you hear on the video clip is a computerized one, coming from Ady Barkan, an ALS patient and advocate for "Medicare for All" who has lost his ability to walk, talk and eat on his own. Seated across from him is Harris, who is meeting with Barkan to talk about health care in the 2020 presidential campaign.

Barkan, who has conducted interviews with several 2020 Democratic contenders, asks Harris about the day she learned her mother, Shyamala Gopalan, was diagnosed with cancer, a topic Harris talks about frequently on the campaign trail.

"You've written that the day your mother was diagnosed with cancer was one of the worst days of your life," Barkan says. "Tell me about that."

Harris slowly tells a familiar story, but then her voice falters.

"She took our hands and she said she'd been diagnosed with colon cancer," says Harris, recalling her mother talking to her and her sister, Maya Harris. "That was one of the worst days of my life, truly. But, you know, it is also, as, you know, and your family knows..."

Harris's face is hard to see in Barkan's video, recorded in a side shot. But her voice is breaking, and she whispers, "Just give me a second."

Harris tears up as she recalls seeing her mother explain that she will die. Gopalan, who raised her daughters as a single mother, would not live to see her daughter run for President.

The California senator attempts to return to the telling the story and explain her vision of health care.

"It is about going through a system that is complicated," she says.

Harris struggles to regain composure, but as she talks, the loss of her mother a decade ago still hangs on every practiced word.

"It is, there are elements of it that work, and elements of it that did not work. Um, give me a second."

Harris is speaking to a terminally ill man on the topic Democrats call among the most personal in their lives. Barkan, 35, was diagnosed in 2016. He is now almost fully paralyzed and conducting the interviews with the aid of a computer that tracks his eye movements and then asks his questions in a synthetic voice.

"You know Ady, I knew this was gonna happen!" says Harris, wiping her eyes with a tissue. Harris laughs to soothe any awkwardness.

"I was like, 'I am not gonna tear up.' I promised myself I was not going to tear up. But you got me," Harris says.