MARTIN LUTHER KING JR., conservative. That description of the civil rights leader whose birth we celebrate today might surprise or even offend many of the people coming to town to celebrate the inauguration of a new president and the supposed triumph of conservatism in some form or other. (The current choices seem to range from Calvin Coolidge to Marine Le Pen.) But in his way, Dr. King did a lot to preserve, protect and defend the best of our principles and values. Just as Franklin D. Roosevelt, who was despised by many conservatives of his day, helped keep American society from succumbing to the radical ideologies that brought death and devastation to much of Europe and Asia, Dr. King worked to turn back extremism, violence and racial nationalism at the height of the civil rights movement, and to keep the cause of essential and long-overdue change in the American mainstream.

The faith that he defended and helped refine was a sort of national creed based on what had come to be widely accepted, after many painful years, as the immutable truth in the Declaration of Independence — that all of us are created equal — and on the idea that Americans are united not by race or by a particular religious belief or ethnic origin, but by our devotion to the concepts of popular government and individual rights.

This is a part of American “exceptionalism,” but through much of our history, a greater part of it could be found in the kind of biblical message that Dr. King carried to the pulpit and the nation. “There is something wrong with our world, something fundamentally and basically wrong,” he told a Detroit congregation in 1954. “The great problem facing modern man,” he said, “is that . . . the means by which we live have outdistanced the spiritual ends for which we live. . . . The problem is with man himself and man’s soul.”

Martin Luther King Jr. preached to us as he knew we were — as he knew he was — flawed beings too often given to cruelty and selfishness, yet capable of being elevated to something higher by the power of divine love. For some, that may seem to be language for the church pew rather than the halls of government. But Dr. King showed that it was the kind of language that can also lead a nation to better itself, to renew its attention to the ideals on which it was founded, to proceed, however unevenly, toward equal justice under the law. Unfortunately, we’ve heard precious little of it, if any, in our national political discourse this past year.

“My friends,” Dr. King said in his Detroit sermon, “all I’m trying to say is that if we are to go forward today, we’ve got to go back and rediscover some mighty precious values that we’ve left behind. That’s the only way that we would be able to make of our world a better world, and to make of this world what God wants it to be. . . .”

Spoken like a true conservative, and a truly great one.