The midterm elections were, to an important extent, a referendum on the Affordable Care Act; health care, not Donald Trump, dominated Democratic campaigning. And voters delivered a clear verdict: They want Obamacare’s achievements, the way it expanded coverage to roughly 20 million people who would otherwise have been uninsured, to be sustained.

But on Friday, Reed O’Connor, a partisan Republican judge known for “weaponizing” his judicial power, declared the A.C.A. as a whole — protection for pre-existing conditions, subsidies to help families afford coverage, and the Medicaid expansion — unconstitutional. Legal experts from both right and left ridiculed his reasoning and described his ruling as “raw political activism.” And that ruling probably won’t be sustained by higher courts.

But don’t be too sure that his sabotage will be overturned. O’Connor’s abuse of power may be unusually crude, but that sort of behavior is becoming increasingly common. And it’s not just health care, nor is it just the courts. What Nancy Pelosi called the “monstrous endgame” of the Republican assault on health care is just the leading edge of an attack on multiple fronts, as the G.O.P. tries to overturn the will of the voters and undermine democracy in general.

For while we may congratulate ourselves on the strength of our political institutions, in the end institutions consist of people and fulfill their roles only as long as the people in them respect their intended purpose. Rule of law depends not just on what is written down, but also on the behavior of those who interpret and enforce that rule.