Republicans have been vowing for six years now to repeal the Affordable Care Act. They have voted to do so dozens of times, despite knowing any measures would be vetoed by President Obama. But the election of Donald Trump as president means Republican lawmakers wouldn’t even have to pass repeal legislation to stop the health law from functioning. Instead, President Trump could do much of it with a stroke of a pen.

Trump “absolutely, through executive action, could have tremendous interference to the point of literally stopping a train on its tracks,” said Sara Rosenbaum, a professor of law and health policy at George Washington University in Washington, D.C.

Trump’s main goal for health care policy is to repeal the Affordable Care Act. That feat will be harder than Trump seems to think, as has been previously reported. To completely repeal and replace the act, he would need 60 votes in the Senate, which is the number needed to overcome a filibuster. Though they’ll make up a majority, there will be only 51 Republican senators come January. He recently signaled in an interview that he may be open to keeping provisions of Obamacare that expand insurance to people with pre-existing conditions and to young people. Trump has also promised to allow tax deductions for child care and elder care and to create tax-free dependent care savings accounts, with matching contributions for low-income families. As was previously reported earlier this year, that would cost the government $25 billion annually.

Trump is set to take office at a tricky time for the health law, with many Americans in both parties complaining about rising premiums and other out-of-pocket costs. The Republican-led Congress has refused to make changes to the law that would help it work better — such as offering a fix when insurers cancelled policies that individuals thought they would be able to keep. As staunch opponents of the law, they, of course, have little incentive to improve it.

When problems have arisen, Obama has often used his executive authority to try to solve them. And it’s this very mechanism Trump could use to undermine the law. As president, the Republican “can just reverse” Obama’s actions in many cases, said Nicholas Bagley, a law professor at the University of Michigan who writes about health policy. A president “can’t undo the basic architecture of the law, but you can throw sand into the gears,” he said. Sarah Kiffsarah at Vox.com wrote that Republicans in Congress have a straightforward path to eliminating key pieces of the Affordable Care Act: They can block the planned insurance expansion in 2017, dismantle Medicaid expansion, and eliminate new insurance marketplaces. That could add up to an incredible blow — possibly causing 22 million people to lose their insurance coverage.

But getting rid of the rest of the law wholesale is a lot trickier. Rolling back provisions — including one allowing young adults to stay on their parents’ health plans and another banning lifetime coverage limits or one banning the rejection of people with pre-existing conditions — would be harder under Senate rules.

This is good news for people who get insurance at work and who benefit from these insurance rules. But it’s little comfort for anyone who buys their own insurance, like a contractor, freelancer, or anyone who isn’t part of a group plan through their employer.

““THEY HAVE A DEATH BLOW TO THE OBAMACARE HEALTH COVERAGE EXPANSION”

” These people could face huge disruptions in their coverage. If Obamacare repeal moves forward without any replacement, they could find themselves facing much higher premiums — or no health insurance plans that want to sell them coverage.

“They have a death blow to the Obamacare health coverage expansion,” says John McDonough, a Harvard University professor who worked in the Senate on the passage of the Affordable Care Act.

We don’t know what, exactly, the future of Obamacare looks like right now or what approach Congressional Republicans will take toward dismantling the law. But after talking to a half-dozen experts over the past few days, it seems likely to me that one of these four scenarios — or some combination of them — will play out.

Which one moves forward matters: Some scenarios allow Republicans to repeal the insurance expansion, but would keep Obamacare rules for the employer market (again, the coverage to age 26 provision and ban on lifetime limits). Some will get rid of everything. The stakes are different depending on what direction Republicans head, and this is a guide to where they most likely will go.

Scenario 1: Trump and a Republican House dismantle major parts of Obamacare via reconciliation, leading to 22 million Americans losing insurance

This is arguably the most plausible outcome at the moments. Republicans unravel Obamacare’s insurance expansion — both the Medicaid expansion and private health insurance marketplaces — which would, according to the Congressional Budget Office, lead to 22 million losing coverage.

Senate Republicans only need 51 votes to get this done. They’d use what is known as the “reconciliation process,” which would allow them to make changes to anything that affects the federal budget. Parts of the law that don’t affect the budget can’t be changed using this process. Last winter, Republicans drafted a bill that would fit the parameters of the reconciliation process. HR 3762 was introduced into the House on October 16, 2015, by Rep. Tom Price (R-GA).

Abbe Gluck, a law professor at Yale University, describes it as “a blueprint for how you might pull the guts out of the Affordable Care Act.” This bill would do a lot to dismantle Obamacare. It would repeal Obamacare’s tax credits for low- and middle-income Americans to purchase insurance at the end of 2017. It would end the individual mandate penalties for not buying coverage. And it would end the Affordable Care Act’s Medicaid expansion at the same time, essentially creating a two-year transition period in which Republicans would presumably consider Obamacare replacement plans.

“REPUBLICANS ALREADY HAVE “A BLUEPRINT FOR HOW YOU MIGHT PULL THE GUTS OUT OF THE AFFORDABLE CARE ACT”

The bill doesn’t abolish Obamacare entirely through reconciliation. It doesn’t, for example, repeal the provision that allows young adults to stay on their parents’ health plans — that doesn’t cost the federal government anything. Congress also couldn’t repeal the ban on annual or lifetime limits for coverage.

Republicans actually don’t bring back pre-existing conditions through this option either — insurance plans would still be required to offer coverage to anyone who wants it.

That being said, this would not be a good situation for people who buy their own insurance. Quite the opposite, experts expect that the individual market would collapse if this repeal bill passed without a replacement plan.

Here’s why: The repeal bill gets rid of the health care law’s key tools to get people to sign up coverage, insurance subsidies to make plans affordable, and the individual mandate to make carrying coverage the law. Without those, premiums would near certainly spike as only the sickest people buy coverage — and health plans would likely flee the market, no longer finding the population an appealing one to cover.

“I think the market self-destructs if you don’t have the premium tax credits or don’t have the mandate,” says Tim Jost, emeritus professor at William and Mary College of Law.

“The private market would collapse, and might no longer exist,” says Nicholas Bagley, an assistant professor of law at the University of Michigan who focuses on health policy.

One other thing to keep in mind about the 2015 reconciliation bill: It’s not the final word on what Republicans could repeal through reconciliation. It is what Republicans came up with in December, when they knew President Obama would veto it.

But now that it has a decent chance at passing, legislators might try and tack on the repeal of other Obamacare provisions — and try to convince the Senate parliamentarian that these pieces also relate to the federal budget.

“The 2015 bill is a floor, but it doesn’t tell us about other sections they might try to include,” says Gluck. “It’s unpredictable what will be judged to have budgetary implications. In 2015, they didn’t need to be careful. They knew their bill wouldn’t pass. Now, they might want to think more carefully about what to include.”

Scenario 2: Trump and the Republican House dismantle major parts of Obamacare through reconciliation — and replace it with something else

Repeal, at this point, feels like political certainty. Republicans have spent six years calling for the end of Obamacare. Now that they have a clear path to make that happen, most experts expect them to follow it.

The remaining question is whether they’re able to follow up with a replacement plan.

“It will be really easy for the GOP to defund the Affordable Care Act and take it away,” says Robert Laszewski, a health care consultant. “The second half of what they need to do is much more difficult. It will be well into fall 2017 at the earliest before a replacement plan might be in effect.”

The clearest outline of what a Republican replacement plan might look like is Speaker Paul Ryan’s Better Way proposal. It includes a refundable tax credit to make individual insurance more affordable and allows insurance plans to sell across state lines.

Better Way would maintain the ban on pre-existing conditions but it would not maintain Obamacare provisions that bar insurers from charging sicker Americans higher rates. So under Better Way, insurance plans would be required to provide coverage, for example, to cancer patients — but could also charge them higher rates.

Better Way does maintain the ban on pre-existing conditions and the provision that allows young adults to stay on their parents’ insurance through age 26.

The Better Way plan is thorough, with a clear vision of what health care might look like under a Trump administration. At the same time, it is still very much an outline — a 37-page document that has broad policy proposals that would need to be hammered out into actual legislation.

“Better Way isn’t in legislative form, and the Senate hasn’t weighed in,” says Chris Condeluci, who worked as tax and benefits counsel for the Senate Finance Committee’s Republicans during the Affordable Care Act debate.

This is why most observers expect it would take at least a year for Republicans to draft and pass an Obamacare replacement plan — and even more than that to write out the regulations and set up the infrastructure in order to implement it.

“The Trump administration, if they like it or not, they’re going to have to run Obamacare for two years,” says Laszewski.

Scenario 3: The Senate eliminates the filibuster and repeals Obamacare outright

Right now, the big thing holding Republicans back from repealing Obamacare outright is the need for 60 votes in the Senate to overcome a filibuster. This pushes them to use the wonky reconciliation process where they can only get rid of the parts that touch the federal budget.

The easy way out of this problem is, of course, to end the filibuster. Democrats already took steps to weaken the filibuster in 2013, and Republicans could decide to eliminate it entirely.

“The ‘right’ to filibuster is fragile: It has never been affirmed in the rules of the Senate, it has always been subject to limitation by precedent, and the 2013 precedent highlighted how easy it is to restrict or eliminate the right,” writes political scientist Gregory Koger.

Without the filibuster, Republicans could pursue complete repeal and replace. Under this scenario, they would be able to end parts of Obamacare that don’t touch the federal budget, like free preventive benefits or the requirement that all people get charged the same premium, regardless of whether they’re healthy or sick.

What comes after repeal, once again, would still be in question — and this scenario, if it does happen, would likely lead to the second scenario in this piece, where Republicans begin to figure out what their replacement plan looks like, and there are questions of whether they pass a replacement at all.

Scenario 4 (possibly concurrent with 1,2, and 3): Trump uses executive action to dismantle certain parts of Obamacare as the Republican Congress needs time to pass repeal

Most of the big parts of the Affordable Care Act need Congressional approval to dismantle. But what President Trump could do unilaterally is re-write some key Obamacare regulations that would alter how the law works.

If you read through the text of the Affordable Care Act, you won’t find any mention of “contraceptives” or “birth control.” That’s because the law doesn’t actually include a mandate to cover contraceptives.

Instead, it says that health insurance must cover preventive health benefits for women — and then punts to a division of Health and Human Services to decide what counts.

It wasn’t always clear that birth control would make the cut. When Obamacare passed, it was a genuine question whether the Obama administration would include birth control in its list. I know because I covered the debate when I was a reporter at Politico at the time. Groups like Planned Parenthood lobbied the White House to include it.

Finally, the administration issued regulations in 2011 announcing that it would include birth control as a preventive benefit for women. A Trump administration could write its own regulation to say birth control isn’t preventive health care for women.

There are other parts of the Affordable Care Act like this. Right now the Affordable Care Act requires insurance plans to cover a set of “essential health benefits.” The law itself contains broad categories, like preventive services and trips to the hospital, but it’s only in regulation where the actual types of care get hammered out. So the Trump administration could write new regulations that significantly reduce what health plans need to cover, and cross a lot of items off the Obama administration’s list.

Formal regulations would take time to undo, because they must follow a lengthy process allowing for public comment. But there are several measures Trump could take on Day One of his presidency to cripple the law’s effectiveness.

Perhaps Trump’s easiest action — and the one that would produce the largest impact — would be to drop the administration’s appeal of a lawsuit filed by Republican House members in 2014. That suit, House v. Burwell, charged that the Obama administration was unconstitutionally spending money that Congress hadn’t formally appropriated, to reimburse health insurers who were providing coverage to working-poor policyholders — those earning between 100 and 250 percent of the federal poverty line.

More than half of people who purchase insurance in the health exchanges get the additional help, which reduces out-of-pocket health spending on deductibles and coinsurance. While that help for consumers is required under the law, the funding was not specifically included. (Tax credits for people with incomes up to four times the poverty level to help defray the cost of premiums are a separate program and were permanently funded in the ACA.)

In April, Federal District Court Judge Rosemary Collyer ruled in favor of the House Republicans. “Such an appropriation cannot be inferred,” she wrote of the payments, and insurer “reimbursements without an appropriation thus violates the Constitution.” However, Collyer declined to enforce her decision, pending an appeal to a higher court. That appeal was filed in July and is still months away from resolution.

If Trump wanted to seriously damage the ACA, he could simply order the appeal dropped, letting the lower court ruling stand, and stop reimbursing insurers who are giving deep discounts to half their customers. That move would wreak havoc, said Michael Cannon of the libertarian Cato Institute, a longtime opponent of the health law. The insurers would still have to provide the discounts, as required by law, he said, “but they’re no longer getting subsidies from the federal government to cover the cost. So they are going to be selling insurance to these people way below the cost of that coverage.”

Even those who support the law say that mismatch would effectively shut down the health exchanges, because insurers would simply drop out. A Trump administration “really could collapse the federal exchange marketplace and the state exchanges if they end cost-sharing” payments to insurers,” said Rosenbaum, who has been a strong backer of the health law. There is already some concern about the continuing viability of the exchanges after several large insurers, including Aetna and United HealthCare, announced they would be dropping out for 2017.

Another way Trump could undermine the health law would be by simply not enforcing its provisions, particularly the individual mandate that requires most people to have insurance. That requirement is supposed to ensure that healthy as well as sick people sign up, thus spreading the costs of people with high bills across a larger population. But “executive branch non-enforcement could make a real difference to the vitality of the exchanges going forward,” Bagley said. If healthy people don’t sign up, sick people would need to pay more money for their insurance.

Aside from inflicting damage to the exchanges, the administration could also affect the law’s operations by refusing to approve states’ changes to their Medicaid programs. States rely on federal regulators to sign off on changes large and small, including which citizens are eligible, to keep their Medicaid programs operating. “There are so many things that an administration that doesn’t want a program to work can do,” Rosenbaum said.

The bigger question, though, is not what Trump could do to cripple the health law — it’s what he would do. He has addressed the issue only rarely — characterizing the health law as, simply, “a disaster” — and his plans for it aren’t clear. “It’s one thing to talk about ripping insurance from 20 million people” who are newly covered, Bagley said. “It’s another to actually do it.”

Health policy analysts on both sides of the aisle also still question where health care fits on Trump’s priority list. “A big unknown is how aggressive Trump would remain in going beyond rhetorically opposing Obamacare,” said Thomas Miller, a resident fellow at the conservative American Enterprise Institute. “His report card as a presidential candidate reads, ‘Donald needs to improve his attention, effort, and study habits. He is easily distracted and seems to prefer just picking fights with others.’ ”

Perhaps most important, Cato’s Cannon says, is not whether Trump could single-handedly undo the health law, but whether he could undermine it enough to force Congress to take action. If Trump were to do just enough to cause the insurance exchanges to fail, he said, “that would put pressure on Congress … to reopen the law.”

But I think that we are now seeing how the GOP and President-elect Trump are re-evaluating their stance on health care. And this is what I have been harping on for many months and many posts. You cannot repeal the Affordable Care Act/Obamacare unless the GOP and President-elect Trump and the Secretary of the HHS have a viable alternative. Otherwise there will be 20-21 million people who had subsidizes under the ACA who will see their coverage disappear. And I believe that this is one of the reasons that our friend Dr. Ben Carson turned down the invitation to take the position to head the HHS.

Just look at Trump’s comments in discussing health care with President Obama in their 90-minute meeting. President-elect Donald Trump said that, after conferring with President Barack Obama, he would consider leaving in place certain parts of the Affordable Care Act, an indication of possible compromise after a campaign in which he pledged repeatedly to repeal the 2010 health law.

In his first interview since his election earlier this week, Mr. Trump said one priority was moving “quickly” on the president’s signature health initiative, which he argued has become so unworkable and expensive that “you can’t use it.”

Yet, Mr. Trump also showed a willingness to preserve at least two provisions of the health law after the president asked him to reconsider repealing it during their meeting at the White House on Thursday

Mr. Trump said he favors keeping the prohibition against insurers denying coverage because of patients’ existing conditions, and a provision that allows parents to provide years of additional coverage for children on their insurance policies.

“I like those very much,” Mr. Trump said in the interview.

Maybe we should give President-elect and the GOP a chance to try to get things right, including health care!

We should all be thankful that we live in this great Country, the terrific people in our lives and opportunities available to all of us.

Happy Thanksgiving!