Democratic presidential hopeful Elizabeth Warren delivered an impassioned explanation of her support for a “Medicare for All,” single-payer health care system in an interview with terminally ill progressive activist Ady Barkan. The nine-minute video capturing Barkan’s discussion with Warren at his home in Santa Barbara, California, released on Tuesday, represents the Massachusetts senator’s frankest discussion to date of a subject matter that she has been more reticent about than other elements of her platform. By contrast, Sen. Bernie Sanders, the Vermont independent who is her closest ideological ally in the crowded Democratic presidential field, has made the policy a central theme of his campaign. Barkan, a 35-year-old attorney living with ALS who now speaks with the help of a computer that reads his eye movements, specifically asked Warren why she supports a single-payer system that gets rid of private health insurance to attain universal coverage, rather than other policies aimed at achieving the same goal. “I think of this as about our values. Health care is a basic human right,” Warren replied. “What we’re trying to do is make sure everyone is covered at the lowest possible cost. And that’s Medicare for All.” Warren went on to reiterate an argument she has made when pressed on the matter in two Democratic debates ― that for-profit health insurance companies whose business depends on charging as much as possible, and paying out as little as they can, are inherently inhumane. Watch Ady Barkan’s interview with Sen. Elizabeth Warren:

But beyond affirming her support for Medicare for All, Warren addressed criticism from left-wing activists who question her commitment to the policy. Although Warren co-sponsored Sanders’ single-payer bill beginning in 2017, she has not made it a major theme on the campaign trail, or produced her own Medicare for All plan with a white paper like she has published on everything from student debt to criminal justice. Barkan asked whether her apparent trepidation about single-payer health care’s most controversial provision ― the elimination of private coverage for any procedure covered by the government ― reflected her affinity for regulation by market forces over “dramatically expand[ing] the size of the public sector.” (Warren has distinguished herself from Sanders, a self-described “democratic socialist,” in part by touting her belief in markets and her identity as a “capitalist.”) “No, I think it was more ... focused on transition than on endpoint,” Warren responded. “But there are areas where markets just don’t work and a big part of health care is one of those. So the idea that we could get a couple of regulations in place and it will sort itself out is just not true with health care.” She added: “I get financial decisions over whether you’re going to be able to get a new car or what it looks like, but not financial decisions at the heart of basic health care. Medicare for All is about a relationship that all of us have to each other.”

Gretchen Ertl / Reuters Sen. Elizabeth Warren of Massachusetts has endured some criticism from progressive activists skeptical of her commitment to Medicare for All.