Harris says a more dramatic change makes sense because a government program like Medicare is the surest, most efficient way to make sure everybody has comprehensive coverage. “We have a Medicare system that’s already working,” Harris wrote in her post. “Now, let’s expand it to all Americans and give everyone access to comprehensive health care.”

Biden’s proposal, which he put forward two weeks ago, would create a new government-run insurance plan but make enrollment in the plan optional, leaving in place most existing insurance arrangements. He is among the many Democrats wary of Medicare for All, because, they say, it would be too disruptive and too difficult to enact politically.

Discussion of how to build on the Affordable Care Act and help Americans still struggling with medical bills has been a dominant theme of the Democratic presidential campaign. The topic is sure to come up when the candidates convene for more debates in Detroit this week, especially on Wednesday night when Harris and Biden, who clashed in last month’s debate , share a stage.

“In America, health care should be a right, not a privilege only for those who can afford it,” Harris wrote in a Medium post introducing her plan.

That means Harris, like all the Democrats running for president, is pushing in a very different direction than President Donald Trump and his Republican allies, whose ongoing efforts to repeal Obamacare would take away coverage from millions and probably tens of millions of Americans.

Exactly where along that spectrum the Harris plan exists depends a bit on your perspective and on some of those details the campaign has yet to provide. But its overall goal is unambiguous. If fully implemented, the Harris plan would result in every American having comprehensive health insurance, achieving an objective that Democrats have been pursuing for nearly a century, most recently with the Affordable Care Act .

Crudely speaking, the Harris plan calls for a more sweeping transformation than the reforms supported by former Vice President Joe Biden . But it would stop short of the change to wholly government-run insurance that Sen. Bernie Sanders (I-Vt.) has championed.

Like many campaign proposals, the Harris plan is more a framework than a point-by-point proposal, with many unanswered questions about the transition, the financing, and other vital matters. Even so, the material from Harris contains enough information to convey the general approach she has in mind and how it compares with the plans from rival candidates.

It would likely replace existing employer-sponsored plans, over the course of a decadelong transition, but it would allow private insurers to offer an alternative form of coverage, much as they do today for seniors on Medicare. The Harris plan would also allow employers to contract directly with companies offering these alternative plans and make them available to employees.

Harris on Monday released a plan to create a new, government-run insurance plan designed to cover all Americans and pay for nearly all their medical expenses.

Sen. Kamala Harris (D-Calif.) has been campaigning for president on a pledge of support for “ Medicare for All .” Now she is telling voters exactly what she means by that.

Drew Angerer via Getty Images Health care came up when the Democratic presidential candidates debated last month in Miami, and it is sure to come up when they debate this week in Detroit.

Harris has talked up Medicare for All previously, but she has frequently followed up with caveats that left her precise policy thinking ambiguous. And although she is a co-sponsor of the Sanders Medicare for All proposal, her new plan is different in several key respects.

One is the transition period, which is more than twice as long as the four-year changeover in the Sanders bill. Harris says her transition will include a series of benchmark tests to make sure the new program delivers affordable, quality coverage.

The plan does not specify exactly how the benchmarks will work or what might happen if, several years into the transition, the fledgling government plan isn’t living up to the standards. But Harris is vowing to set up a “commonsense path” to the new system and says the option to buy into Medicare will be available to everybody right away.

“This will likely be a point that is criticized, but … I actually think the timeline is the most realistic for moving a country toward something like Medicare for All,” Kavita Patel, a physician, Brookings fellow, and former Obama administration official, told HuffPost. Patel, with whom the campaign shared its proposal beforehand, said, “Senator Harris is clearly trying to lay out a more pragmatic version of Medicare for All.”

Another big difference between the Harris and Sanders proposals is the role of private insurance, which has become a flashpoint in the Democratic primary debate.

Harris would allow private carriers to continue offering Medicare Advantage plans, which is the private insurance alternative already available to senior citizens in Medicare. But under Harris’ scheme, those Medicare Advantage plans would not simply be for seniors. Anybody could choose to enroll in them.

Employers could have a role, too. They contract with insurers to offer insurance directly to employees, as long as it met the same high standards for benefits and the employees still had the option of enrolling in the government-run plan instead.

At a time when candidates like Biden are talking about leaving private insurance system largely in place and creating a “public option” for people who want it, the system Harris envisions is a bit like the opposite: creating a government-run insurance system but creating a “private option” for people who want it.

Another way to think of the plan is that it would replicate the existing Medicare structure for seniors, although with some key enhancements. The new plan would have much more generous benefits, for example. Like the insurance available under the Sanders bill, the Harris plan envisions no major out-of-pocket spending for the services covered, including basic medical, dental and vision services.

And under the Harris plan, the government would regulate the Medicare Advantage plans more tightly than it does today and reimburse them at rates closer to independent estimates of their actual costs. “If they want to play by our rules, they can be in the system,” Harris said of the private insurers. “If not, they have to get out.”

An Effort To Address Voter Qualms

A senior campaign official told reporters over the weekend that these tweaks to the Sanders plan grew out of discussions Harris had with analysts and voters over the last few months, since she first made plain her support for Medicare for All, even though it would end employer coverage.

“As she talked to people during the campaign ― and if you’ve been on the trail with her, you know she listens as much as she talks ― and consulted with health experts, she identified ways to make it better and more responsive to concerns and anxieties she’s heard,” the official said.

Exactly how many people would end up in the private option is impossible to say. Roughly one-third of all seniors are in Medicare Advantage today and it is safe to assume that most of the nation’s biggest insurers would be offering a version of this coverage under the Harris plan. That could make the private option a familiar, potentially attractive source of insurance to Americans who might be wary of a new government plan.

Employers could seek out private plans for the same reason ― although, as with individuals, interest would ultimately depend on whether private insurers, operating under closer government scrutiny, can actually offer a competitive product.

“My bet is that most employers would stop offering health benefits once their workers have access to Medicare for all,” Larry Levitt, executive vice president for health policy at the Henry J. Kaiser Foundation, told HuffPost. “But, if the Medicare plan proves less attractive than private insurance, lots of employers might keep providing coverage to attract employees with good health insurance like they do today. ”

Just the idea of a private option might ease anxieties over making enrollment in a new government plan mandatory. Polls have shown repeatedly that Medicare for All’s support drops if voters think it means displacing private insurance altogether. But keeping private insurance also means keeping private insurance bureaucracies, which can mean more complexity and waste, as well as more denials of treatment for seemingly arbitrary reasons.

Don Berwick, a physician and former director of Medicare and Medicaid during the Obama administration, was among the experts with whom the campaign shared the plan beforehand. He praised its “strong commitment to covering everyone,” and noted the private insurance option meant that “many people can likely keep commercial insurance if they want it, as in Medicare Advantage today.”

But, Berwick also said, “The same feature ... maintains the inefficiencies of private insurance and a multi-payer system, with its inherent complexities.”

The Response From Biden And Sanders

The Biden campaign was quick to attack Harris, arguing that she had changed her position and was still pushing a plan that would require too much disruption and too many new taxes.

“After she launched her campaign for president, Senator Harris confirmed her support for the Sanders bill, but then, after being pressed about the ramifications of denying voters the choice of private health insurance plans, began a long and confusing pattern of equivocating about her stance on health care in America,” the Biden campaign said. “That pattern has now taken yet another twist.”

The Sanders campaign also accused Harris of backtracking. It warned that her plan would leave too many Americans at the mercy of for-profit insurers while driving up costs for everybody. Writing on Twitter, Sanders campaign manager Faiz Shakir wrote: “Let’s take a popular, good government-run program. Add a lot more privatization and profit-seeking into it. What could go wrong?”

Whatever its consistency with past rhetoric, the Harris plan has many unknowns ― like how it would pay providers and what steps, if any, the government would take to keep existing employer plans in place during the long transition. And although a senior campaign official told HuffPost the program “would not prohibit access to the plan based on legal status,” the official didn’t specify exactly how undocumented immigrants would fit into it.

The Harris plan does have a financing component. It would apply an “income-related premium,” as the Sanders plan would, but set a higher income threshold, $100,000 per household, for when those premiums kick in. The Harris plan would also use money from a new tax on investment trades.

The campaign says the proposed funding is adequate to cover the plan’s costs and is consistent with a promise Harris made not to tax the middle class. But given the cost of health care, even the most generous proposals out there typically assume that middle-class people pay something toward the cost of care, just as they do today, through some combination of premiums, taxes and out-of-pocket costs.

The article has been updated to include comments from the Biden and Sanders campaigns, as well as additional information about the role of employers provided by the Harris campaign after introducing its plan publicly.