(AP) — Kamala Harris insists she still backs “Medicare for All,” but the health care proposal she released on Monday stops short of the full-scale health care system overhaul that her more liberal 2020 Democratic presidential rivals are advocating.

In a split with Bernie Sanders, Medicare for All’s chief architect and a fellow White House hopeful, Harris said she envisions a role for private insurers as long as they follow the government’s rules. She would slow the transition to a so-called single-payer system to 10 years from the four Sanders has proposed. And she has ruled out tax increases on middle-income Americans, an idea to which Sanders has expressed openness in exchange for lowering the price of health coverage.

Medicare for All has become a defining issue in the Democratic primary, with the most progressive candidates calling for a revolutionary approach to providing insurance coverage for all Americans at a lower price. Harris’ proposal, released a day before the second round of presidential debates begins, essentially seeks to thread the Democratic Party’s disparate camps, nodding to the demands of the progressive base while acknowledging that some voters are nervous at the prospect of losing private coverage provided by their employers.

But it also could open Harris to criticism that she’s trying to appease all corners while doing little to stake out a position of her own. She’s already had to repeatedly clarify her positions on fundamental aspects of the Democratic Party’s health care battle, including the role of private insurers.

A top adviser to Joe Biden, with whom Harris memorably clashed during the first debate, blasted the California senator’s plan as a failed attempt to please all sides in the debate and warned that her decision to push a 10-year transition obscures the full cost of her approach.

“This new, have-it-every-which-way approach pushes the extremely challenging implementation of the Medicare for All part of this plan ten years into the future, meaning it would not occur on the watch of even a two-term administration,” said Biden’s deputy campaign manager, Kate Bedingfield. “The result? A Bernie Sanders-lite Medicare for All and a refusal to be straight with the American middle class, who would have a large tax increase forced on them with this plan.”

Harris also got hit from the left over her health care tightrope walk. Sanders campaign manager Faiz Shakir accused her of “continuing her gradual backdown from Medicare for All” and suggested that she had been inconsistent on the issue of health care.

Although Harris signed onto Sanders’ Medicare for All legislation in Congress and credited the Vermont senator on Monday for “making sure this is a front and center topic,” she distanced herself from his strategy.

“I have a vision of what it should be, and the existing plans that are being offered did not express what I wanted,” Harris told reporters while campaigning in Detroit.

Topher Spiro, vice president for health policy at the left-leaning think tank Center for American Progress, lauded Harris for trying to assuage “concerns that people have about disruption and about an abrupt transition” away from a largely employer-based health insurance system.

Spiro likened Harris’ plan to the current design of Medicare and Medicaid, which he said “shows it’s possible to have a government program that provides benefits through private options that is very cost-efficient.” He declined to say whether he consulted with the campaign on its plan beyond providing information on Medicare Extra, his group’s proposed alternative to Sanders’ Medicare for All.

Advocates of Sanders’ single-payer insurance plan were quick to criticize the Harris proposal. Adam Gaffney, the president of Physicians for a National Health Program, said Harris’ plan has “several major shortcomings,” including the continuation of private insurance and the longer transition period.

“This plan continues to give private insurance a very central role in the health care system,” he said. “We have seen for decades that that does not work.”

Harris has repeatedly been forced to clear up her stance on Medicare for All. She has previously appeared to suggest that she supported abolishing private insurance, later clarifying that she does not.

Sanders and Harris will debate on different nights during this week’s second primary debates, so they won’t clash directly on health care. But liberals who will share the stage with Harris, including New York City Mayor Bill de Blasio, could press the issue.

Sanders said this month that the sweeping overhaul of the U.S. health system he envisions could cost up to $40 trillion over a decade, and he has said that one option for paying for part of that hefty price would be a 4% tax hike on families making more than $29,000 each year.

Harris is calling for exempting households making less than $100,000 each year from that 4% tax, with “a higher income threshold for middle-class families living in high-cost areas.” While Sanders estimated that his proposed tax increase would raise $3.5 trillion over 10 years, Harris did not specify how much revenue would be raised in the scenario she’s proposing.

To pay for the difference, Harris wants to tax stock trades at 0.2% of the value of the transaction, 0.1% for bonds and 0.002% for derivatives.