Story highlights

Bernie Sanders won the support of former Democratic Party Chairman Paul Kirk, but cannot escape questions about his health care plan

Sanders promised again that he would release details of his plan before the Iowa caucuses

Washington CNN  — 

Bernie Sanders on Thursday stood by his pledge to outline his health care plan before the Iowa caucuses amid criticism from Hillary Clinton and conflicting statements from within the Vermont senator’s campaign about whether he will meet his own deadline.

“What this plan does, of course, is end private insurance payments for the American people,” Sanders said during a campaign stop at Dartmouth College. “So instead of making a private insurance premium payment, you’re now going to make a Medicare premium payment. And what all of the studies indicate is that payment under a Medicare-for-all single-payer system will be significantly less than what middle class families today are paying for health insurance.”

Sanders campaign manager Jeff Weaver said as recently as Wednesday that the campaign does not yet have a date for when to release the Medicare-for-all plan.

Asked when he would release details of how his plan would be paid for, Sanders first said, “the truth is we already have a plan,” referencing his 2013 proposal for expanding Medicare, but later said, “certainly before Iowa.”

Sanders is running neck and neck with Clinton in Iowa, just a few weeks before Democrats head to the caucuses there.

The tightening of the race this month has spurred the two to resume attacks on each other which had remained largely dormant through most of December. Clinton, in particular, has pressed Sanders to explain precisely how he would pay for his Medicare-for-all plan.

Sanders, meanwhile, has wrestled with an earlier campaign pledge not to run negative ads against Clinton, raising the question of what counts as an attack ad.

The Sanders campaign, meanwhile, rolled out the endorsement of Paul Kirk, a Kennedy family confidant, as they have been gaining steam in Iowa and pulling away from Clinton in New Hampshire.

Kirk, who was appointed to fill former Sen. Ted Kennedy’s seat in 2009, praised Sanders’ commitment to overturning Citizens United and restoring campaign finance limits if elected.

“The unlimited amounts of money flooding our political system from a narrow and immensely wealthy slice of American society is the most pernicious internal peril threatening the fundamental tenets of economic, political, moral and social justice and, not least, the fairness and vibrancy of our representative democracy,” Kirk said.