Senate Minority leader Chuck Schumer (D-N.Y.) urged Republicans hoping to repeal President Obama's health care law, Jan. 4, to show Democrats what the alternative would be first. (Reuters)

It was no small feat for Republicans to suffer an embarrassing public defeat on the very first day of the new Congress, but they managed to do it by first voting to gut the Office of Congressional Ethics, then reversing themselves within hours after a public outcry and a spate of bad press. This is likely to be a Democratic talking point for a long time to come (“The first thing Republicans did was try to destroy the ethics office!”).

But more than a mere embarrassment, it points the way for Democrats to win the most important battle of the opening year of the Trump administration: the one over repeal of the Affordable Care Act.

Let’s begin with what happened with the OCE. Republicans in the House had something they wanted to do: Remove the threat of pesky ethics investigations. They had the votes to do it, so they did, in the belief that the political fallout would be limited enough to make the whole thing worthwhile. What they didn’t count on was that the news media would be drawn to the story and give it front-page treatment, or that Democrats, liberal organizations, and individuals using social media would quickly mobilize to get people to contact their representatives to express their outrage.

And it worked. TV news and newspaper headlines all attributed the reversal to Donald Trump’s supposedly heroic tweet on the subject, which didn’t even oppose the move, just its timing. But in reality, as reporters working Capitol Hill reported, what really turned the tide was the public backlash, namely the flood of angry phone calls and emails to Republicans’ offices complaining about the move to gut the OCE. Republican members got spooked enough to quickly reverse themselves.

It was a demonstration of a time-honored principle, that politicians live in a constant state of terror, and what they’re terrified of is the public’s displeasure. Make that displeasure large and visible enough, and they’ll abandon even initiatives they care deeply about.

Which brings us to ACA repeal. There’s something rather remarkable happening right now: Republicans are essentially pushing the throttle all the way forward on the repeal train before they’ve even laid the track that will take them to their destination — and to boot, they don’t know what that destination is. On one hand, they’ve made a commitment to their base to repeal the law, a commitment they feel is impossible not to fulfill. But they’re beginning to understand that it’s easy to say you’ll do that when you don’t have to be responsible for the consequences. And in this case, the consequences will be absolutely catastrophic, starting with kicking at least 12 million people off Medicaid and leaving out in the cold another 9 million who can only afford the coverage they get through the exchanges because of the substantial subsidies they get.

Republicans hope that eventually their version of the health insurance system will bring down the cost of coverage so much that some day those 21 million people will be able to afford to buy coverage on their own. Almost everyone who knows anything about this subject understands that hope to be wildly optimistic at best, if not utterly ludicrous. But even if Republicans are right, it would take years, years in which those millions would be without coverage.

Meanwhile, a gigantic political threat looms over them. Toss all those millions of Americans off their insurance, and the news will be filled with horror stories of people who found themselves without coverage because of what Trump and the Republicans did. People will suffer. People will die. And they won’t be able to blame it on Barack Obama.

Which is why Republicans can’t figure out what to do. Many of them are advocating a “repeal and delay” strategy, under which they’ll repeal the law now and figure out later what to replace it with. Even conservative health wonks say that’s crazy, partly because the individual insurance market would probably collapse as insurers fled even before the repeal took effect. While they try to figure out what they’ll replace the ACA with, Republicans are piling up promises they can’t keep, saying that “no one” will be worse off under that as-yet-nonexistent replacement. Those pledges are preposterous, and should be used to demonstrate just how disastrous the Republicans’ plans are.

Which brings us to the Democrats, and how they can derail the repeal train before it plows through the American health care system and destroys untold numbers of lives. Here are some things they need to do:

Show Americans what they’ll lose. It’s a fundamental truth of life and politics that we’re much more highly motivated by losing something than we are by gaining something (psychologists call this “loss aversion”). But most people don’t know exactly what “Obamacare” is in its particulars and what they stand to lose under repeal. So those losses need to be the focus of Democrats’ attention: the millions who’ll lose coverage, the millions whose pre-existing conditions will make them vulnerable once again, the seniors who won’t be able to afford their medications. When Democrats talk about this issue, they don’t need to bother trying to convince people that Obamacare is great; they need to focus on the specific harms repeal will do.

Act locally. As the ethics office story showed — and as the Tea Party knew well — people contacting their members of Congress, and getting in their faces when they’re at home in their districts, is incredibly powerful. Members need to feel afraid of their constituents, to raise the political cost of repeal above the ideological satisfaction they’ll get from it. Activists need to find out exactly how many people in every district and state will be affected by repeal, and make sure their representatives know it too.

Tell the stories. There are millions of people who have been helped by the ACA, and who stand to lose everything if it disappears. Tell those stories. Spread them on social media. Get them on the news.

Build a coalition. The American Medical Association, a reliably conservative group that claims to speak on behalf of the nation’s doctors, just released a letter to Congress arguing that a replacement plan must be presented before the ACA is repealed, and insisting that “it is essential that gains in the number of Americans with health insurance coverage be maintained.” Last month the American Hospital Association issued a similar appeal, warning that the nation’s hospitals stand to lose hundreds of billions of dollars if the law is repealed.

Then there’s that most terrifying of constituencies, senior citizens. Once they learn that repealing the ACA means reopening the “donut hole” in Medicare’s prescription drug coverage, potentially costing them thousands of dollars for the medications they rely on, they aren’t going to be too happy, either. Republican members of Congress should hear from as many directions as possible that they’re courting disaster.

Don’t compromise. For six years, Democrats have said to Republicans, “Sure, the ACA isn’t perfect, so why don’t we fix the specific parts of it that could work better?” Republicans refused, insisting that it had to be repealed completely. Democrats need to take a similar line now, namely that they’d be happy to work with Republicans to address specific health care reforms, but only once repeal is off the table. They can’t negotiate the details while Republicans are holding a gun to the heads of tens of millions of Americans.

Even though Republicans have control of both houses of Congress and the White House, and insist that repealing the ACA is their highest legislative priority, this is a battle Democrats can absolutely win. Whatever repeal plan Republicans come up with will give them all the ammunition they need. And they only have to convince three Republicans in the Senate (where the split is 52-48 in favor of the GOP) to put the brakes on repeal, and the battle is over, for now, at least.

That’s achievable if Democrats keep in mind that fighting Trump and the Republicans isn’t about venting their anger or doing whatever makes them feel good. It’s a practical task with discrete components that have to be planned and executed. This could be the most consequential battle of the entire Trump presidency, and it starts right now.