Without using her name, Biden also snuck in a dig at Harris’s support of Medicare-for-all, which she says would eliminate the need for private insurance beyond supplemental coverage. Asked about his approach to the next debate, Biden brought up health care as a subject on which he will be ready to spar.

“I have some people saying, ‘No, I’m not going to do away with Obamacare. We can still have supplemental insurance,’ ” Biden said. He contrasted Harris’s insistence that she would pay for the enormously expensive program with a tax hike on the wealthy and Wall Street, whereas the measure’s author, Sen. Bernie Sanders (I-Vt.) has said he will raise taxes on the middle class.

“Bernie’s been honest; he’s going to raise taxes on middle class,” said Biden, whose health-care plan would expand Obamacare and create a government-run insurance plan to compete with private insurers.

“Well, you’ve got to find 30 to 40 trillion dollars somewhere. And how are you going to do it? Well, I find that people would say that, for Medicare-for-all, they’re not going to tax the middle class because you don’t need to do that!” Biden added. “Come on! What is this, is this a fantasy world here?”