Any day now, the U.S. Supreme Court may make possible something that has yet to happen: an honest and complete discussion of the Patient Protection and Affordable Care Act (ACA).

And if it throws out all or part of the law now popularly known as “Obamacare,” we will need a fearless conversation about how a conservative majority of the court has become a cog in a larger right-wing project to make progressive political and legislative victories impossible.

I still harbor the perhaps naïve hope that some conservative justices — Anthony Kennedy? John Roberts? — will pull back from judicial activism and allow the voters to decide the fate of the health-care law in this fall’s elections. And here is where the court’s reintroduction of the health-care issue into the political debate could be turned into a blessing by allies of reform, provided they take advantage of the opportunity to do what they have never done adequately up to now. They need, finally, to describe and defend the law and what it does.

The ACA is the victim of a vicious cycle: Obamacare polls badly. Therefore, Democrats avoid Obamacare, preferring to talk about almost anything else, while Republicans and conservatives attack it regularly. This makes Obamacare’s poll ratings even worse, which only reinforces the avoidance on the liberal side.

The media have abetted the problem, but this is partly a response to the impact of the vicious cycle on how the issue has been framed. As a study by the Project for Excellence in Journalism has shown, terms used by opponents of the law, such as “government-run,” were much more common in the coverage than terms such as “pre-existing conditions.”

Maybe now, supporters of the ACA will find their voices and point to the 30 million people the law would help to buy health insurance, how much assistance it gives businesses, how it creates a more rational health insurance market, how it helps those 26 and under stay on their parents’ health plans, how it protects those with pre-existing conditions. “Obamacare” isn’t about President Obama. It’s about beginning to bring an end to the scandal of a very rich nation leaving so many of its citizens without basic health coverage. However the court rules, we need to remember why this whole fight started in the first place.

If the court does strike down the law, those concerned that criticisms of its ruling might undermine the “legitimacy” of the judiciary should put their worries aside. Conservative justices long ago shattered the court’s standing as a nonpartisan, non-ideological actor in our governing system. That’s why recent surveys have found its approval rating on the decline.

As retired Supreme Court Justice John Paul Stevens noted 12 years ago in a powerful dissent, the court’s Bush v. Gore decision threatened “the nation’s confidence in the judge as an impartial guardian of the rule of law.” It’s gotten worse since. The 2010 Citizens United decision stands as another ruling that plainly strengthens conservative monied interests in the electoral arena. Please don’t tell me that these justices are entirely without a political agenda.

But friends of the health-care law need to acknowledge upfront that no matter how effectively they criticize the court, a ruling against it would be a real defeat — for the president, for the cause of expanding insurance coverage, and for progressives generally. Neither Obama nor his congressional allies would have wasted the time and political capital entailed in passing health-care reform if they had known that their efforts would be struck down by the judiciary even before the law came fully into force.

Enacting any sort of health-care reform is, as we have seen repeatedly since Harry Truman called for universal coverage, a gargantuan task. Balancing the many interests involved (and, ironically, the individual health-insurance mandate was a concession to conservative interest groups) is exceedingly difficult. For unelected judges to give the back of their hands to legislators whose job is to solve problems while accounting for competing priorities would be the height of arrogance and a flight from democracy. But all the liberal anger in the world will not make up for the size of the setback.

Were the health-care law to be eviscerated, those who battled so hard on its behalf might draw at least bittersweet comfort from what could be called the Joni Mitchell Rule, named after the folk singer who instructed us that “you don’t know what you’ve got till it’s gone.”

ejdionne@washpost.com