Buoyed by popular-vote wins in Iowa and New Hampshire and small donations from millions of supporters, Bernie Sanders enters the Nevada caucus with the lead in 10 national polls, with forecasters predicting his victory with as much as 32 per cent of the vote.

But the Democratic frontrunner is facing a fresh round of attacks on his vision of Medicare for All, which would expand the program by enrolling every American into a comprehensive "single-payer" healthcare plan, free at the point of service, without monthly enrollment costs, co-pays and costly deductibles.

Donald Trump and Mike Bloomberg have raised red-scare flags. Pete Buttigieg warns that the senator's ambitious plan would explode the growing deficit. But it's the health lobby that has spent millions on advertisements as well as candidates' campaigns, stoking fears about Americans' health insurance disappearing overnight and hoping to drown out support for his signature proposal.

"My former employers see this as an existential threat", says Wendell Potter, a former health insurance executive who has emerged as a vocal Medicare for All advocate. "It's the quest for profits that has led to the spiraling spending on health care, and has developed to a situation where we don't have a health care system but a sickness industry."

As the US prepares for an election at which the future of medical care is at stake, Mr Potter is sounding the alarm for the "mother of all propaganda campaigns" while Medicare for All is attacked from all sides.

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His exodus from his 20-year career with health insurance giants Cigna and Humana has manifested into his ongoing whistle-blowing effort to expose the industry's political and media manipulations to combat a plan that could make the multi-billion dollar business obsolete.

The US currently relies on a multiple-payer system, with insurance companies, government programmes or other services covering care for millions of Americans. Medicare for All would consolidate Americans into one government "plan", giving the US leverage to drive down costs.

Just as the Affordable Care Act (ACA) invoked the wrath of conservative lawmakers a decade ago, the renewed fight over future American healthcare is shaping together "right out of the industry playbook", one Mr Potter helped write to push back against the ACA's reforms.

"I saw that campaign being implemented", he says. "I was getting pissed off, quite frankly ... I saw the work I was doing showing up in the media ... I couldn't stay on the sidelines."

'It's finally not working for most people'

While the field begins to reshape after losses in the first two primary states, the Vermont senator's ground game in Nevada is stronger than his opponents' with 10 offices and 200 staffers, a quarter of whom are Latino, campaigning in the Silver State.

Mr Sanders also has the most union support among candidates, counting more than a dozen in all that support his Medicare for All plan, including National Nurses United, the largest union of registered nurses in the US.

But Nevada's largest and most politically powerful union has refused to endorse a candidate. The Culinary Union, representing 60,000 hospitality workers, released a flyer on the night of the New Hampshire primary singling out Mr Sanders' health plan, which would "end Culinary healthcare".

Culinary 226 Secretary-Treasurer Geoconda Arguello-Kline announced "we're not going to endorse a candidate" but instead will "endorse our goals". The union also didn't endorse in 2016.

A one-page flyer summarising several candidates' positions posits that Mr Sanders will "end Culinary healthcare" while it says that Elizabeth Warren will "replace Culinary healthcare" with a three-year transition plan or at the end of existing collective bargaining agreements. Both candidates endorse Medicare for All.

Culinary Union's healthcare plan, administered through a nonprofit trust, provides care for 130,000 people, including union members and their families.

The union didn't explain to its members that Mr Sanders' plan would guarantee healthcare for all union members, and all Americans, regardless of their employment. Striking workers wouldn't lose their care, for example, and supporters argue that a guaranteed medical plan would allow unions to organise around other crucial benefits, like higher wages, once employers are no longer on the hook for paying partial costs of their employees' healthcare.

The flyer drew swift condemnation from Mr Sanders' supporters while his opponents seized the moment to express their support for the union and pitch their health plans.

Mr Sanders' chief opponent among the Democrats – former South Bend, Indiana mayor Pete Buttigieg, who paced neck-and-neck with Mr Sanders for delegate votes in Iowa and New Hampshire – shared on Twitter: "There are 14 million union workers in America who have fought hard for strong, employer-provided health benefits. Medicare for All Who Want It protects their plans and union members' freedom to choose the coverage that's best for them."

Mr Potter, in response, said that Mr Buttigieg's attack on Medicare for All "will thrill my old pals in the insurance industry, as Pete's plan preserves the very system that makes them huge profits while bankrupting [and] killing millions."

He told The Independent that candidates leaving room for private insurers – like Mr Buttigieg's "Medicare for All Who Want It" and the introduction of a "public option" alongside the preservation of private insurance companies – "is still leaving in place the foundation of a system that is absolutely dismal and overly expensive".

"If you just add the public option you're leaving in place the very reason why our system is so darn expensive", he says.

Mr Buttigieg's campaign also is supported by significant donations from the health industry, which spent more than $3m on the candidate in 2019.

But that support is dwarfed by the army of insurers, drug companies hospitals and other groups that have waged a war against Medicare for All and to protect the Affordable Care Act, the last major Democratic victory on healthcare.

Partnership for America's Health Care Future and other groups have lobbied to suppress Medicare for All and legislation that would expand the government's role in administering healthcare.

The organisation is an alliance of hospital and insurance groups, including the Federation of American Hospitals, America's Health Insurance Plans, the Pharmaceutical Research and Manufacturers of America, the American Hospital Association and the Blue Cross Blue Shield Association.

Its latest campaign includes ads airing on MSNBC and NBC websites, including a Spanish-language version, features actors worrying about their families losing private insurance care and higher taxes, claiming that "government-controlled proposals could double" their income taxes.

The group argues that Americans would be "forced to pay more" to "wait longer for worse care" under a system "run by politicians" – which Mr Potter says are among the talking points he assembled while working for insurance companies.

Timothy Faust, a single-payer advocate and author of Health Justice Now: Single Payer and What Comes Next, says decades of "fraud and inefficiencies" have proved too lucrative for the industry to give up.

"If you're a big hospital corporation or private equity firm that owns a hospital, a benefits manager, an insurance company – all of this fraud and all of this waste is how you line your pockets," he tells The Independent.

With the average insurance deductible tipping over $4,000 while 40 per cent of Americans don't have $400 for a medical emergency, "the contradictions are too great" to preserve the status quo, he says. "It's finally not working for most people."

'Fear, uncertainty and doubt'

Mr Buttigieg has attacked Mr Sanders for the high cost of enacting a Medicare for All plan – estimates are as high as several trillion dollars over 10 years. Rather than pay into deductibles, co-payments and other costs, Americans would pay into the programme through higher taxes. But at least five analyses from the last decade have argued that a single-payer programme would significantly drive down current costs.

The most recent study from Yale University found that a single-payer plan could save Americans more than $450bn in health costs and prevent 68,000 unnecessary deaths every year. Families would see an average of $2,400 in annual health savings.

"In this case single payer is the financially prudent choice," Mr Faust says. "Plans like Buttigieg's kind of continue that grovelling to insurance companies ... to keep this stupid thing afloat."

Many Americans are currently insured through plans provided by their employer, which ultimately negotiates a plan for its employees. If an employee leaves the job, changes jobs or is fired, they lose that insurance, unless they elect to continue to pay for it for a brief period, often at a higher rate than when they were employed.

But there remain 37 million uninsured people in the US, while more than 40 million others are under-insured, paying overwhelming out-of-pocket costs or, in some cases, facing bankruptcy to pay for their medical bills.

Insured Americans still are paying thousands of dollars in monthly premiums, annual deductibles, co-pays and other out-of-pocket expenses for treatment even when covered within an insurance network. Costs for seeing providers that aren't covered by the insurer outside the network can skyrocket those costs.

Insurance companies are engaged in messaging campaigns around "fear, uncertainty and doubt" - also known as "FUD", Mr Potter says.

"They're very skilled at that, they know there's little accountability, and few people know what they're up to," he says.

A disinformation campaign – targeting the importance of "choice" and "competition" in healthcare – obfuscates the lack of choice in private insurance carriers, as Americans are limited by in-network doctors and the often-prohibitively expensive cost of seeing providers out of network.

Employers ultimately choose what their employees get, and that freedom to "choose" goes both ways – at-will employment gives companies the freedom to sack their staff, leaving them without insurance.

"Single payer represents an emancipatory movement for people in America," says Mr Faust, who argues that guaranteeing insurance for all Americans could relieve workers from poor quality jobs or help people escape abusive relationships that rely on partners' insurance coverage.

Mr Potter also warns against the opposition's message that eliminating private insurance will "stifle innovation", despite massive investments from government programs like the National Institutes of Health into private companies at taxpayers' expense.

He says fear over the "government takeover of healthcare" is "one of those messages that has been tested in focus groups" while conservatives have sowed distrust about the role of government to boost support for the private sector.

Claims that a nationalised health plan is "out of step with American values" also send him back to the fight over the Affordable Care Act, as one group – the health lobby – determined mattered most to Americans.