Unable to stop Republicans from hastily confirming Judge Amy Coney Barrett to the Supreme Court, Senate Democrats have spent much of the past two weeks predicting that she will push the high court to kill the Affordable Care Act. And that, in turn, will leave more than 20 million Americans without health insurance during a pandemic, while also eliminating key protections for people with pre-existing conditions.

It's a scary possibility, yet whether Barrett is the ACA's executioner is far from certain. That's true despite her now well-known (and not subtle) criticism of Chief Justice John Roberts' reasoning when he voted in 2012 to uphold the ACA's mandate that adult Americans maintain health insurance coverage.

To recap quickly, writing for the 5-4 majority, Roberts held that the mandate was a constitutional exercise of Congress' power to tax because it was enforced with a tax penalty. On Nov. 10, the Supreme Court is scheduled to hear arguments in a case (California v. Texas) that once again challenges the constitutionality of the ACA, this time because the GOP-controlled Congress in 2017 eliminated the insurance mandate's tax penalty. A federal judge in Texas ruled in December 2018 that the mandate was now unconstitutional and so the entire law needed to be thrown out; the Fifth Circuit Court of Appeals agreed on the constitutionality question but sent the case back to the original judge, Reed O'Connor, to look more carefully at whether the rest of the law could be left in place. Rather than waiting for O'Connor to deliver another bizarre ruling, a group of Democratic attorneys general asked the Supreme Court to hear their appeal. And that's where we stand today.

Democrats have rightly flayed the Trump administration for urging the justices to throw out the entire ACA. And if the administration gets its way, Democrats have rightly noted how bad the consequences will be for anyone with insurance through the ACA. Those who lose group coverage would also be threatened by insurers' regaining the ability to discriminate against people with pre-existing conditions in the individual market.

Still, Barrett's views about Roberts' reasoning are moot this time around. The Supreme Court is a different set of justices considering a different set of facts.

Even before they get to the constitutionality question, the court has to grapple with whether the 18 Republican-led states and two individual plaintiffs should have been allowed to bring the lawsuit in the first place. It boggles the mind that anyone could claim to be injured by an insurance-buying requirement that's unenforceable. There is literally no penalty for not complying.

If the government passes a law requiring you to fly to Saturn, you are not injured if you can ignore it without penalty. And if you are not injured, you cannot sue. That should end the discussion.

But if five or more justices manage to contort themselves into seeing actual injuries to the plaintiffs, the next question will be whether the mandate to buy insurance is constitutional. The tax penalty that Barrett and Roberts split on is no longer in play; in fact, it's no longer a mandate — people are free to buy or not buy coverage. There's no governmental overreach because there's no power exerted. The three Trump appointees on the court, none of whom were involved in the 2012 ruling, could conceivably side with the court's three liberals, as could Roberts.

Finally, even if five or more justices find the mandate to be unconstitutional, there's still the question of whether the rest of the law can survive. And in this area, Barrett's ascension to the high court could potentially prove fatal to the ACA.

The justices have generally imposed a two-part test to determine whether an offending provision or provisions can be "severed" from a law, leaving the remainder in effect. First, they determine whether the law works as intended minus the provision(s), and then they determine whether Congress would have passed the law had it known the provision(s) would be removed by the courts.

On both issues with the ACA, the answer is a resounding yes. The tax penalty enforcing the mandate has been gone for three years, and contrary to the fears of many (myself included), the individual insurance market did not fall into a death spiral of ever-increasing premiums and ever dwindling enrollment. Analysts say that premiums are a few percentage points higher than they would be with a mandate, but across the country, average premiums have declined the past two years. So yes, the law is continuing to work as Congress intended.

Would Congress have passed the law without the mandate? No question, the mandate was crucial to winning the support of insurance companies for the ACA. But it was also the toughest thing for lawmakers to support; they did so mainly because it was billed as a necessary counterweight to the ban on insurers discriminating against people with pre-existing conditions, which lawmakers were eager to enact. Only later did we see that it wasn't, in fact, necessary.

So it's conceivable that Congress would not have enacted two of the ACA's key insurance reforms — the requirements that insurers offer policies to everyone who applies and that premiums not be affected by pre-existing conditions — without the individual mandate. But that wouldn't have stopped the Democrat-controlled House and Senate from passing the rest of the ACA, with its expansion of Medicaid to millions of poor Americans and its efforts to improve the quality of care while slowing the increase in cost.

All of these calculations involve consulting the legislative history and doing at least a little bit of mind reading, two things that Barrett and other originalists/textualists do not like to do. That's why the most conservative members of the court — and most notably Justice Clarence Thomas — don't want the courts to do the sort of severability analysis that the Supreme Court has been doing. They consider that to be legislating, not judging.

Here's how the four dissenters to the 2012 ruling, who would have tossed the entire ACA, put it: "The Judiciary, if it orders uncritical severance, then assumes the legislative function; for it imposes on the Nation, by the Court's decree, its own new statutory regime, consisting of policies, risks, and duties that Congress did not enact. That can be a more extreme exercise of the judicial power than striking the whole statute and allowing Congress to address the conditions that pertained when the statute was considered at the outset."

Two of those four dissenters are no longer on the court, however. So even if Barrett follows Thomas' lead, both of Trump's other appointees — Justices Neil M. Gorsuch and Brett M. Kavanaugh — would have to do so as well for the entire ACA to be sunk.

Barrett tried several times to downplay the concerns the Democrats on the Senate Judiciary Committee raised about the ACA, even as she assiduously avoided any legal theorizing that might tip her hand. "The presumption is always in favor of severability," she said when asked about the general issue. And at another: "I'm not here on a mission to destroy the Affordable Care Act."

She'll join the bench soon enough, and when the court issues its ruling in a few months, we'll see whether she tried to do just that.