WASHINGTON — Soaring jobless claims are poised to leave millions of Americans without health insurance coverage during the coronavirus pandemic.

The emergency highlights a flaw in the U.S. system that's unique in the developed world: About half of Americans get coverage from their employers. Health care, already a top issue for voters, is about to become even more salient as many wonder what the system would look like if President Donald Trump, Democratic front-runner Joe Biden and Democratic underdog Bernie Sanders had their way.

"In all three proposals, whether people are insured or uninsured, they would likely get care if they showed up at a hospital with COVID-19. The question is: How does that care get financed?" said Sabrina Corlette, a research professor who directs Georgetown University's Center on Health Insurance Reforms.

"In the Sanders plan, it's very clear — the government picks up the tab for that almost 100 percent. In the Biden plan, for the most part either the government or your employer would pick up the tab. You might have to pay some deductible or cost-sharing," she said. "In the Trump world, it largely falls to the consumer or patient — or the hospital eats the cost or tries to pass it on to employer-based plans."

Here's a guide to what uninsured Americans can do today and how the Biden, Sanders and Trump plans would change the system.

Current system

Jobless people who just lost their coverage have several options.

One is to sign up for coverage through the Affordable Care Act, or ACA, also known as Obamacare. They can enroll in Medicaid or buy a subsidized plan on the exchanges, depending on their income. Some may fall into a coverage gap if they live in the 14 states that declined the expansion of Medicaid and make too much for Medicaid but not enough for Obamacare assistance, which kicks in at the federal poverty level of $12,760 for an individual without kids.

Unemployment benefits count as income for this purpose.

"If you lose your job-based coverage, you have 60 days to sign up for an ACA pre-exchange plan. You can actually do that before you lose your job-based coverage. So if you find out in advance that you're being laid off, you can go to the exchange and line up your coverage immediately," Corlette said.

Another option is to extend an employer-based plan under COBRA by paying 102 percent of the cost of the plan. Employer-based plans tend to be expensive, so this option will be unaffordable for many.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Download the NBC News app for breaking news and politics

Biden plan

The Biden plan can be understood as Obamacare-plus. He'd preserve the employer-based system, boost subsidies to help uninsured people buy coverage and add a "public option" to the Obamacare exchanges that would compete with private insurers. In essence, people would sign up the same way they do now but with more generous government assistance.

"The Biden plan is a beefed-up version of the status quo," said Loren Adler, associate director of the USC-Brookings Schaeffer Initiative for Health Policy. "A big part of the ACA's aim was to create a safety net for health coverage for dislocations like this. Biden's plan is a pretty generous bump-up of those subsidies."

People in the Medicaid coverage gap — who live in states that declined the expansion — would be enrolled in the new public option at no cost. Others would be able to use their subsidies to shop between the private options and public plans. The Biden plan would lift the maximum income threshold for subsidies, which is over $50,000 today, and boost them so they fall as a share of income.

"So if you expect to make more than $50,000 this year, you'd also now have access to subsidized coverage," Adler said.

Sanders plan

The Sanders plan is the simplest. He proposes to put every American in Medicare from birth to death — no ifs, ands or buts. Insurance premiums, deductibles and out-of-pocket costs would be eliminated. Prescription drug costs would be each year $200 per person. Private insurance would effectively be eliminated, and losing one's job would have no impact on coverage.

"It's cradle-to-grave coverage," Corlette said. "Your insurance coverage would no longer be linked to your employer, so some of the real disruption and pain we're seeing with people being laid off would not exist. Everyone would be in the same plan regardless of how and whether they're employed."

Taxes would rise to cover what the nonpartisan Urban Institute estimates would be a mammoth $3 trillion-per-year cost, although overall national health care spending would fall. Sanders says the COVID-19 crisis highlights the need for "Medicare for All," as it would end the link between employment and coverage.

Critics say his system would force cuts in providers' pay and limit the availability of care.

"There are questions about what our provider workforce would look like under a single-payer plan, whether everybody would have equitable access, whether there would be issues of shortages and delays," Corlette said.

Trump plan

Trump's plan is the most opaque. His latest budgets and his support for a lawsuit before the Supreme Court show he wants to eliminate Obamacare. But it's not clear what he'd put in its place, as he has not backed a particular plan since his push to replace the law failed in Congress in 2017.

"There's a little bit of trying to hide the eight ball, but they are taking almost all the money out of the ACA," Adler said. "Fundamentally it is: Let's bring things back to the pre-ACA world."

Wiping out Obamacare could end coverage for about 20 million low- and middle-income people who have gained it under its subsidies, expanded Medicaid and other provisions. Insurers could also deny coverage for pre-existing conditions, charging sick people more and rescinding policies.

"I'd be shocked if they didn't say: 'You didn't tell me about your diabetes. You didn't tell me you have lung problems, that you have asthma, and that's why you have COVID-19, so I'm not going to cover your COVID-19 treatment,'" Adler said.

Such a system could bring back low-cost plans that cover a narrow set of services, which were eliminated by Obamacare and tend to be sought by young and healthy people.

Trump promises to protect pre-existing conditions, although he hasn't explained how. Asked what the president's plan is to protect the uninsured jobless from COVID-19, a White House spokesman referred to Trump's comments on Thursday, in which he said it was a work in progress.

"We're doing a lot of different things on health insurance. We have meetings on it today," the president told reporters, noting that individuals would be getting one-time checks of up to $1,200 under the stimulus package. "This was not a financial crisis. This was a health crisis, a medical crisis. We're going to take care of our people."