But her ideas to pay for it, Mr. Gleckman said, were vague.
“She talks about rolling back some provisions of the 2017 tax cut bill, but she never says exactly which ones,” said Mr. Gleckman, who assessed the cost of Ms. Harris’s plan at almost $3 trillion over a decade. “She talks about raising taxes for higher-income people, but she never says how.”
As to the ideological quizzes that have flummoxed her, Ms. Harris said she regarded some as essentially unserious. In other cases, she said they triggered her instinct as a former government lawyer to measure her words carefully because they could leave a mark.
“My orientation, again, is to really want to think through the details of how will this actually play out,” she said.
The most persistent questions have concerned single-payer health care. Ms. Harris has endorsed legislation written by Mr. Sanders to enact such a system, but has gradually distanced herself from core elements of that plan. Most recently, she told a CNN reporter in Davenport, Iowa, that she backed “Medicare for All,” but added a confusing caveat: She also opposed the middle-class taxes that are currently envisioned as an essential funding mechanism.
She maintained that stance in the interview, saying she had an alternative source of funds in mind. “Stay tuned,” she said.
Ms. Harris also said the transition from a private health insurance system to single payer would require much more concerted planning before it became a workable policy.
“This thing sounds great,” she said, “but how are we going to actually get there?”
If Ms. Harris’s resistance to ideological sorting has hobbled her at times, her allies do not expect her approach to change. They see it as an essential personality trait. Louise Renne, a former city attorney of San Francisco who mentored Ms. Harris, called her a “nonideological” person motivated by “the issues of diversity, honesty and transparency in government.”