OAKLAND — U.S. Sen. Kamala Harris announced Wednesday that she intends to support a congressional effort to expand Medicare to all Americans.

“I intend to co-sponsor the Medicaid-for-All bill,” California’s junior senator told several hundred people at a town hall at Oakland’s Beebe Memorial Cathedral, referring to Vermont Sen. Bernie Sanders’ Medicare-for-All proposal.

The bill, which Sanders plans to introduce next month, is essentially single-payer health care. It would expand the federal Medicare program, which mostly covers people age 65 and older, to all Americans. (Medicaid, which Harris mistakenly referred to, is a joint federal and state program that provides health coverage to the poor.)

Harris, who previously had said she supported the concept of single-payer health care but hadn’t come out in favor of any specific bill, is the first senator after Sanders to publicly endorse his plan. She said she was backing the bill “because it’s the right thing to do.”

“Health care should be a right, not a privilege,” she said. “This should not be a partisan issue. It shouldn’t even be a bipartisan issue. It should be a nonpartisan issue.”

She also argued that a single-payer system care would make fiscal sense.

“It is so much better that people have a meaningful access to affordable health care at every stage of life — from birth onward,” she said. “The alternative is that taxpayers are paying huge amounts of money for them to get health care in an emergency room.”

Sanders thanked Harris in a tweet. “Let’s make health care a right, not a privilege,” he said.

Thank you @KamalaHarris for your support. Let's make health care a right, not a privilege. https://t.co/hYbxTq8BVH — Bernie Sanders (@SenSanders) August 30, 2017

Single-payer health care has become one of the key issues of the progressive movement. More than half of Democrat House members support a single-payer bill written by Rep. John Conyers, D-Michigan. Other Democratic senators who are talked about as potential 2020 presidential contenders, including Massachusetts Sen. Elizabeth Warren and New York Sen. Kirsten Gillibrand have also supported single-payer without publicly endorsing Sanders’ bill.

But passing a single-payer system would be extremely difficult in a Republican-controlled Congress.

Universal health care remains a point of contentious political debate within California. A single-payer health bill that passed the state Senate earlier this year was held up in the state Assembly, provoking anger from activists. Assembly Speaker Anthony Rendon argued that the bill was not ready for prime-time because it didn’t specify how California would pay for the measure.

Speaking with reporters after her town hall, Harris said that she’s “always supported the concept” of Medicare for all. And she argued that the idea wasn’t necessarily hopeless, even in a Republican-dominated Congress.

“As we talk about moving toward a single-payer system, there is certainly momentum and energy around that,” she said, noting that voter anger led to Congress failing to repeal the Affordable Care Act this summer.

Beyond the Medicare issue, Harris’ town hall was more or less a lovefest for the hometown Senator — her first event since she took office to be held in Oakland, where she was born. An enthusiastic Harris discussed a range of issues, from President Donald Trump’s plan to end the DACA policy to education to political organizing.

The Trump administration, she said, is “requiring us to stand up, be vocal, and fight,” she said, repeating the word fight more than 15 times in the hour-and-15 minute event.

It was a notably different tone than that of California’s other U.S. Senator, Dianne Feinstein, who was booed at her town hall the night before after encouraging her audience to be patient with Trump and saying he could “be a good president” if he learns and changes his approach.

Asked about Feinstein’s comments, Harris told reporters she didn’t want to speak for her colleague, but noted, “everything that this president has done in the last eight months leads me to believe that he has spoken his intentions, he has spoken his values… I have no reason to believe he is going to change course.”

In one moment of levity, Harris encouraged an Oakland business owner asking her a question to tell her about her business.

“It’s a sex shop,” replied the questioner, Nenna Joiner, and Harris let out a surprised “Oh!” The entire room burst into laughter.