Elizabeth Warren has nominally thrown her support behind the idea of Medicare for All, a proposal that has enjoyed growing popular support since Bernie Sanders put it on the map in 2016. But fearful of a right-wing backlash, Warren is hesitant to echo Sanders in saying that the program will raise taxes. Her refusal has left many scratching their heads about how she plans to pay for single-payer health care.

At the most recent Democratic Party presidential debate, the moderators repeatedly asked Warren if Medicare for All would impose a tax increase on ordinary families. She responded each time with various iterations of her prepared remark: “I will not sign a bill into law that does not lower costs for middle-class families.”

Her supporters praised her for not giving the Right a sound-bite to manipulate, but it’s not clear the evasion worked in her favor. “At least Bernie is being honest here, and saying how he’s going to pay for this and that taxes are going to go up,” responded Amy Klobuchar. “And I’m sorry, Elizabeth, but you have not said that and I think we owe the American people to tell them where we will send the invoice.”