His campaign released details Wednesday of how Sanders will pay his $1 trillion dollar infrastructure plan and his $75-billion-a-year plan to make public college and universities tuition-free. But noticeably absent was his plan to pay for Medicare for all, a price tag that some estimates put at $15 trillion.
Jeff Weaver, Sanders' campaign manager, isn't saying when those numbers will be released.
"I don't have a date for that," he said earlier this week. "Not necessarily before the caucuses."
Weaver stood by his comments on Wednesday, stating that the campaign does not yet have a date for when to release the Medicare-for-all plan. He added that Sanders' health care plan would be paid for "progressively," similar to the way his previous Medicare-for-all proposals have been paid for.
That's a change from what Sanders first told Dana Bash on CNN's "State of the Union" earlier this month
that he would release his details for paying for his health care plan before the caucuses on February 1. Bash pressed the Vermont senator again on Tuesday after President Barack Obama's final State of the Union when she asked if Sanders would make good on his pledge to release his single payer plan.
"Absolutely," Sanders said. "If I said we're going to do it that's what we're going to do."
Hillary Clinton's campaign is seizing on the issue as polls show a tightening Democratic race in Iowa. After spending weeks mostly slamming Sanders for his stance on guns, Clinton and her aides are expanding their critique of the senator to include health care.
"Senator Sanders has some very big ideas, but he hasn't yet told anybody how he would pay for them," Clinton told CNN's Alisyn Camerota earlier this week
. "And he had promised that he would roll out his tax plans before the Iowa caucus on February 1. Well, if you wait too long, nobody will have a chance to see them or analyze them."
Clinton press secretary Brian Fallon said Wednesday that Sanders not releasing the details of his plan before Iowa is "alarming."
"We think that the caucus goers in Iowa deserve to hear form Senator Sanders about how he will pay for this single proposal," he said in a conference call with reporters.
Clinton used a large portion of a speech she gave in Ames, Iowa, on Tuesday to contrast herself with Sanders. After outlining his Medicare-for-all plan, which she argues would collapse the current health care programs that people rely on, Clinton said, "If that is the kind of revolution he is talking about, I am worried, folks."
"There is no way that can be paid for without raising taxes on the middle class. The arithmetic just doesn't add up," Clinton said. "I don't think that is the right way to go."
When Sanders introduced a single-payer bill in 2013
, the bill was to be paid for through "an equitable system of progressive taxation, payroll taxes and re-allocation of current dedicated health care expenditures by the federal, state and local governments."
Sanders' campaign responded aggressively Wednesday morning, tweeting a signed photo of Clinton working with the Vermont senator.
"'To Bernie Sanders with thanks for your commitment to real health care access for all Americans...'-@HillaryClinton," the tweet states
, transcribing the caption from Clinton's handwritten note.
The campaign also accused Clinton of flip-flopping in a statement put out shortly after the tweet.
"Clinton's attacks on a Democratic Party rival over universal health care marks a very public flip flop by her and her campaign. She is now using the same Karl Rove tactics she once decried," the statement said.
If Sanders' health care plan did raise middle class taxes, the senator would violate another pledge he made in December when he told NBC that his paid family leave would be the only measure he would raise taxes on the middle class to fund.