Sen. Bernie Sanders' campaign is blasting rival Democratic presidential contender Sen. Kamala Harris over her repeated insistence that she’s “not prepared to engage in a middle-class tax hike” to pay for her "Medicare-for-all" proposal.

Painting the California Democrat’s plan as unrealistic, senior Sanders campaign adviser Jeff Weaver said: “I don’t know how you can fund health care for everybody without paying for it.”

“Without unicorns, magic wands, health care is not free. There’s doctors, nurses that have to be paid. There’s hospitals. You have to pay for it,” he added in an interview on MSNBC.

SANDERS DEFENDS HIS MEDICARE-FOR-ALL PLAN

Weaver spoke on Wednesday, the same day that Sanders gave a major address outlining and defending his Medicare-for-all, single-payer health care proposal.

Medicare-for-all, in which essentially all Americans would obtain their health insurance from a government-operated program like Medicare, is backed by Sanders, Harris, Sen. Elizabeth Warren of Massachusetts and a number of other the contenders in the record-setting field of some two-dozen 2020 Democratic White House hopefuls.

Sanders – the independent senator from Vermont who’s making his second straight bid for the Democratic presidential nomination – explained earlier his week in an interview with the Washington Post that his plan would cost $30 trillion-40 trillion over a 10-year period. But he compared that to the $50 trillion he said it would cost to continue the nation’s current health care system.

THE LATEST FROM FOX NEWS ON THE 2020 PRESIDENTIAL CAMPAIGN

But Harris isn’t on board with a tax increase for individuals.

“I’m not in support of middle-class families paying more taxes for it,” she told CNN on Wednesday.

The senator explained that she’d pay for her plan in part by having “Wall Street paying more. Part of it is going to be looking at what we tax in terms of financial services. That is part of it.”

“There are ways to pay for it understanding the investment we are going to be making in a way that is going to reap great benefits in terms of other costs,” Harris added as she noted the massive costs associated with people without insurance who currently seek treatment. “American health and in what we are otherwise paying in a cost for people not having access to health care and the burden that places on systems across the board when people don’t have access to health care.”

And she argued that the price tag shouldn’t hinder the implementation of a Medicare-for-all plan, saying “the status quo is not enough so we have to be open to challenging the status quo so everyone has access to health care and price is not the barrier. We have to agree that what is happening right now is not affordable to many, many working families.”

BIDEN TAKES AIM AT HARRIS OVER MEDICARE-FOR-ALL

The current front-runner in the Democratic nomination race – former Vice President Joe Biden – opposes Medicare-for-all.

But last week, campaigning in the first-in-the-nation presidential primary state of New Hampshire, he complimented Sanders on how he’d pay for his plan.

“Bernie's been very honest about it. He said you're going to have to raise taxes on the middle class. He said it's going to end all private insurance. I mean, he's been straightforward about it. And he's making his case," Biden told reporters.

When asked if other Democratic White House hopefuls are as straightforward about their support for the single-payer system, the former vice president answered, "well, so far, not. So far, not. They may.”

Asked specifically by reporters if Harris has been honest about whether her version would end private insurance, Biden answered, "I'll let you guys make that judgment.