Just one week after the Nov. 3 elections, the Supreme Court will hear arguments in a lawsuit backed by President Trump that seeks to overturn the Affordable Care Act (ACA).

The death of Justice Ruth Bader Ginsburg and the nomination of Judge Amy Coney Barrett, whose confirmation would shift the balance of the court significantly to the right, has put the 2010 law in greater danger.

While the ACA's fate is still uncertain — many legal experts in both parties think the lawsuit’s arguments are so weak that even conservative justices would uphold the law — the consequences of it being struck down would reverberate through almost every corner of the health care system.

“It’s an enormous disruption,” said Larry Levitt, a health policy expert at the Kaiser Family Foundation. “It would result in immediate chaos in the health care system.”

Here’s a rundown of what would happen if ObamaCare is struck down.

20 million people would lose health insurance

About 20 million people who gained health insurance through the law, both through its expansion of Medicaid and through subsidized private plans on newly created “exchanges,” would lose coverage if it is struck down.

A December study from the Urban Institute put the number at 19.8 million, a figure that would lead to a 65 percent increase in the uninsured rate.

Some states, particularly those that expanded Medicaid, would see particularly sharp spikes in the uninsured. Montana would go from 63,000 people without coverage to 175,000, the study found. California would go from 3.4 million to 7.2 million.

The pandemic-related job losses mean that even more people are likely relying on ObamaCare coverage now.

“My guess is 20 [million] is a low estimate at this point,” said John Holahan, a fellow at the Urban Institute who worked on the study.

Pre-existing condition protections would be gone

Striking down ObamaCare would also mean the law’s immensely popular protections for people with pre-existing conditions would go away.

Insurers in the individual market, meaning the market for people buying health insurance not through their employers, would be able to return to the pre-ObamaCare practices of charging people more or simply denying them coverage outright if they had costly health conditions.

The Kaiser Family Foundation estimates that almost 54 million Americans have a pre-existing condition that would lead to them being denied coverage if they could not get insurance through a job and had to try to buy on the individual market without ObamaCare’s protections.

Many Republican lawmakers, after years of strong opposition to ObamaCare and passage of a 2017 GOP bill in the House that would have weakened pre-existing condition protections, are now expressing their support for those provisions, meaning it is possible at least those sections could be restored by Congress if the law were struck down.

But those provisions on their own would have major holes. Many people with pre-existing conditions would still be unable to afford coverage without the ACA’s financial assistance, for example.

Adults up to age 26 would not necessarily be able to stay on parents’ plans

Another part of the ACA that has gained widespread appeal is the requirement that young adults up to age 26 can stay on their parents’ health insurance plans.

If ObamaCare were struck down, that requirement would go away, and it would be up to each employer to decide whether to keep the provision for their health plan.

Levitt said the labor market would play a role in determining whether employers choose to keep the benefit.

“Certainly some employers would maintain it,” he said. “It would be a hard benefit to take away.”

Tax cuts would mainly benefit the wealthy

Striking down ObamaCare would also do away with taxes imposed on high earners that were used to pay for the law.

The law created a 0.9 percent tax on earnings and a 3.8 percent tax on investment income for couples making more than $250,000.

The top 0.1 percent of incomes would get 42 percent of the tax cuts from repealing ObamaCare, for an average tax cut of almost $200,000, according to an analysis by the left-leaning Center on Budget and Policy Priorities. The lowest fifth and second-lowest fifth of incomes would each get 3 percent of the tax cuts, for an average tax cut of about $50.

“Striking down the ACA would thus transfer billions of dollars each year from low- and moderate-income people (who would lose subsidized health coverage) to high-income households and corporations (which would receive large tax cuts),” the analysis said.

A whole range of other things

The ACA included a slew of provisions that have almost nothing to do with the core features of the law but that would still be eliminated if the Supreme Court invalidated the statute in its entirety.

Those provisions range from requiring chain restaurants to post calorie counts on their menus, to shielding seniors on Medicare from out-of-pocket drug expenses in what is known as the “donut hole,” to setting up a center to test innovations in Medicare and Medicaid aimed at saving money and improving quality.

Trump is relying on that Center for Medicare and Medicaid Innovation to implement one of his signature policies aimed at lowering drug prices by tying them to lower prices in other countries. If ObamaCare were struck down, the authority for that initiative would disappear.

Tom Miller, a health policy expert at the right-leaning American Enterprise Institute, said that while the number of uninsured would rise if ObamaCare were struck down, he does not think it is likely the Supreme Court will do that, and the case is mostly being used by Democrats for campaign attacks.

“There is a political market of predictions of the worst case and the extremes,” he said.