What does it mean to have civil debate? How do we get back to it, given the deteriorating state of public discourse? These are questions I am often asked because of my closeness to someone who for so many people represented what political dialogue in this country should strive to be: my late father, Charles Krauthammer.

There are many principles he embodied that led him to maintain the highest standards of argument. I discuss them at length in the preface to the new paperback edition of his posthumous book, “The Point of It All.” But my father was particularly fond of one phrase that sums up so much of what is essential: “the loyal opposition.”

Originally a British parliamentary term, it encapsulates a concept critical to democracy: that whoever holds power, all sides must respect the fundamental legitimacy of their political rivals; that their differences be seen not as treasonous or out of bounds, but rather as healthy disagreement within our divided and adversarial system of government, which as a whole — and only as a whole — retains ultimate authority. Members of the other party may be your opponents, but within the walls of our democratic constitutional order, they are not your enemy. Where freedom and pluralism reign, you must convince, not overpower.

What does this mean in practice? Above all, it means meeting the other side face to face in a battle of ideas, respecting their right to promote their viewpoint and recognizing that winning the debate means mounting the superior argument: using sounder reasoning and marshaling more compelling evidence. And it means not attempting shortcuts to victory by trying to delegitimize the other side before the debate even begins.

My father never resorted to these shortcuts and often focused his withering criticism on them when used as a crutch by those unwilling or unable to mount a cogent argument. One such strategy is villainizing the opposition. When we contend that those with differing views are not just wrong but are bad people — criminals even — we abandon genuine debate. If we hold that their conclusions stem not from faulty logic or evidence but from fundamental ill will and nefarious intentions, then no progress can be made. No one ever changed their mind because their opponents called them evil.

A second, twin strategy that my father criticized was apocalyptic alarmism. He identified the clearest historical examples appearing on the left with the Nuclear Freeze movement of the 1980s and on the right with the McCarthyite conspiracy hysteria of the 1950s. The motivations and assumptions for each are different, but the basic argument is the same: The other side’s program is leading to the destruction of all we hold dear, and certain disaster can be avoided only by following our own side’s particular political path. With the stakes so high — sometimes even the literal end of the world — everything else becomes secondary. Procedural obstacles — even constitutional ones — become intolerable. The only justifiable option becomes overpowering the opposition by any means necessary.

In today’s politics, neither side of the political divide has a monopoly on such hyperbole. We hear partisans on both sides claiming that their adversaries are full of evil intent and hatred; that if their own party doesn’t win, America will be lost forever.

Such strategies are good only for rallying those who already agree with you; for whipping them into a panic; for making them less willing to even consider the other side’s position and more willing to do whatever it takes to keep others out of power or — even more drastically — to silence them.

This mind-set undermines open discourse and democratic principles. As my father once wrote, “Those who believe that the end of the world is coming and that they hold the key to preventing it, tend to believe that their program is good — indeed, absolutely necessary — for all. They become convinced of their obligation to carry out their mission, and impatient with those standing in their way.” It is an approach “marked by a profound intolerance, which not only rigs the terms of the debate . . . but often abolishes debate altogether.” Liberal democracy does not fare well in this environment. In the end, “apocalyptic politics demands a declaration of emergency. But democracy never coexists well with emergency, a lesson we have always learned during wartime.”

In contrast, my father came to the national debate with humility and in good faith. He saw his political sparring partners as mistaken and perhaps ill-informed, but still as fundamentally decent and well-intentioned souls who wanted the best for their country, too. He sought to dismantle their arguments and ideas, not to assault their character. And he never presumed his arguments so obviously right that they could be opposed only by those wishing harm or destruction on the nation or the planet.

This is not to say my father was a moral relativist who didn’t recognize evil in the world or existential threats to our way of life. Far from it. As a student of history, he was keenly aware of the power of politics gone wrong to wreak untold destruction on our civilization. But that historical awareness gave him the perspective to see just how far our current situation is from how bad things can truly get; how lucky we are to live in a stable, open and prosperous democracy; and how essential it is for us not to lose that perspective or exaggerate our internal disagreements to the point where we start characterizing the other side not as “the loyal opposition,” but instead as enemies of the state. Down that road lies the fate of banana republics, lands of civil strife and civil war. And so, my father wrote, “That is reason enough to resist the sirens calling us to the moral equivalent of war.”

My father appreciated the incredible preciousness and also the fragility of the democratic system we are blessed to have inherited. He recognized that it is neither the natural nor an automatic state of being for society. It is the exception in human history, and it takes great and continual effort — the hard work of democracy and of civil debate — to sustain it. It is, he wrote, the “ceaseless work of every generation. To which I have devoted much of my life.”

May the next generation find inspiration in his example.