“I think the approach that we have, in fact, will be much more progressive in terms of protecting the financial well-being of middle income families,” Sen. Bernie Sanders told ABC News on Saturday, alleging that Warren’s proposal could have a “very negative impact” on middle-class job creation.

“I think we have a better way, which is a 7.5-percent payroll tax, which is far more I think progressive, because it’ll not impact employers of low wage workers but hit significantly employers of upper income people,” added Sanders, who last week told CNBC’s John Harwood that he would not release a plan outlining how to pay for his proposal.

Former Vice President Joe Biden, meanwhile, who has lambasted universal Medicare coverage as unfeasible, accused Warren of lying about the bill being funded without tax increases on the middle class.

“She’s making it up,” Biden told PBS NewsHour after the plan was released. “There is no way.”