(Reuters) - Perhaps no issue has divided the field of Democratic 2020 presidential hopefuls more than “Medicare for All.”

Eight 2020 Democratic presidential candidates are seen in a combination image from file photos (L-R top row): Billionaire Tom Steyer, U.S. Senator Elizabeth Warren, U.S. Senator Bernie Sanders and former U.S. Vice President Joe Biden (L-R bottom row): South Bend, Indiana Mayor Pete Buttigieg, former New York City Mayor and billionaire Michael Bloomberg, entrepreneur Andrew Yang, and U.S. Senator Amy Klobuchar. REUTERS/Files

Liberal candidates favor the sweeping proposal, which would replace private health insurance with a single government-run plan. Moderate candidates have embraced less drastic measures they say would achieve broader healthcare coverage while allowing individuals to choose their plan.

Here is where the top eight contenders stand on Medicare for All:

MEDICARE FOR ALL OR BUST

Bernie Sanders

The U.S. senator from Vermont authored Medicare for All legislation that would essentially abolish private insurance in favor of a single government-run plan that covers every American. The ambitious proposal would cost more than $30 trillion over 10 years, according to independent analyses.

Sanders has acknowledged he would impose higher taxes on families to help pay for the program, but has argued the typical middle-class family would save overall by eliminating virtually all health expenses.

The bill would transform Medicare - now primarily for Americans aged 65 and over - into a universal system and ban employers from offering healthcare plans to compete with the government. Aside from prescription drugs, patients would face no out-of-pocket costs when accessing medical services.

Several Democratic rivals, including former Vice President Joe Biden, have criticized Sanders’ plan as unrealistic.

Elizabeth Warren

Perhaps more than any other candidate, Warren, a U.S. senator from Massachusetts, has grappled with the issue of Medicare for All. After initially saying she was “with Bernie,” she released a detailed financial proposal in November with a price tag of $20.5 trillion in additional government spending over a decade.

Warren vowed to finance the plan with higher taxes on the wealthy and corporations while avoiding “one penny” more in middle-class taxes.

The idea was met with skepticism by some of her Democratic rivals, including Biden.

Warren subsequently released a transition plan. It would create a public option - similar, albeit more ambitious in scope, to that proposed by more moderate candidates like Biden. It would preserve private insurance for three years before fully implementing Medicare for All.

That proposal drew some criticism from the left, with Sanders supporters claiming she had backed down from her Medicare for All stance. Warren has said she remains committed to Medicare for All and that her plan would provide more coverage to more Americans in a shorter time frame.

PREFERRING A PUBLIC OPTION

Joe Biden

The No. 2 to Democratic President Barack Obama has criticized Medicare for All as an effort to dismantle the Affordable Care Act (ACA), Obama’s signature healthcare law.

Instead, Biden has vowed to “build on” the ACA, popularly known as Obamacare, by adding a public option that would leave the current private insurance system in place.

His healthcare plan, estimated to cost $750 billion over 10 years and paid for partly by higher taxes on the wealthy, would let people enroll in a paid government healthcare plan as an alternative to private insurance. The government plan would be modeled on Medicare and available even to workers with employer-provided policies.

The proposal would also expand the ACA’s subsidies for private policies, making them more generous and extending them to more people.

Michael Bloomberg

The billionaire former mayor of New York, who entered the campaign in November and is skipping the first four state contests, released a healthcare plan in December that would create a public option but preserve the current system of private and employment-based insurance.

Bloomberg has advocated building on the ACA, rather than scrapping it in favor of a Medicare for All plan that he says is unaffordable. He has called for increasing subsidies to cover low-income families’ premiums.

His plan would cost $1 trillion in additional government spending over 10 years. Bloomberg’s campaign aides have said he will release details on how he would finance it in the coming weeks.

Pete Buttigieg

Buttigieg, the former mayor of South Bend, Indiana, favors a public option, which would allow individuals to opt into a government plan but would preserve the existing role for private insurers.

Buttigieg, who coined the phrase “Medicare for all who want it” to describe the concept, has argued that a public option will eventually lead to a single-payer system because individuals will find that Medicare is more cost-efficient than private policies.

The plan would cost $1.5 trillion in additional spending over 10 years, according to the campaign. Buttigieg has said he would pay for the plan by rolling back President Donald Trump’s corporate tax cuts.

Amy Klobuchar

Klobuchar, a moderate U.S. senator from Minnesota, has said she would improve on the ACA by adding a public option that would be available through either Medicare or Medicaid, giving people the chance to choose a government-backed plan. She has called Medicare for All a “pipe dream.”

She has said she would finance her legislation in part by raising taxes on the wealthiest Americans.

Tom Steyer

Steyer, a billionaire who entered the race in July, favors a public option that would allow Americans to choose a government-backed plan while expanding on the ACA.

His proposal would cost $1.5 trillion over 10 years, according to his campaign.

STAKING OUT A MIDDLE GROUND

Andrew Yang

Yang, an entrepreneur, has said he supports “the spirit of Medicare for All.” He has argued that the prevailing job-based insurance system discourages businesses from hiring due to ever-rising costs, while forcing people to stay in jobs they dislike to protect their healthcare coverage. However, he has said he would not seek to ban private insurers.

He has bemoaned the amount of time that Democrats have spent debating Medicare for All and has focused instead on issues like lowering drug costs, improving technology and transitioning doctors from a fee-for-service model to a salary-based system.