Dr. Dobson is not alone. Jerry Falwell Jr., the president of Liberty University, has praised Mr. Trump's life as in many ways exemplary and said that he believes that "Donald Trump is God's man to lead our nation." Eric Metaxas, who has written popular biographies of William Wilberforce and Dietrich Bonhoeffer, has rhapsodized about Mr. Trump and argued that Christians "must" vote for him because he is "the last best hope of keeping America from sliding into oblivion."

And should your conscience tell you that Mr. Trump might not be the right choice, Robert Jeffress, the influential pastor of First Baptist Church in Dallas, explains that "any Christian who would sit at home and not vote for the Republican nominee" is "motivated by pride rather than principle."

This fulsome embrace of Mr. Trump is rather problematic, since he embodies a worldview that is incompatible with Christianity. If you trace that worldview to its source, Christ would not be anywhere in the vicinity.

Time and again Mr. Trump has shown contempt for those he perceives as weak and vulnerable -- "losers," in his vernacular. They include P.O.W.s, people with disabilities, those he deems physically unattractive and those he considers politically powerless. He bullies and threatens people he believes are obstacles to his ambitions. He disdains compassion and empathy, to the point where his instinctive response to the largest mass shooting in American history was to congratulate himself: "Appreciate the congrats for being right."

What Mr. Trump admires is strength. For him, a person's intrinsic worth is tied to worldly success and above all to power. He never seems free of his obsession with it. In his comments to that gathering of evangelicals, Mr. Trump said this: "And I say to you folks, because you have such power, such influence. Unfortunately the government has weeded it away from you pretty strongly. But you're going to get it back. Remember this: If you ever add up, the men and women here are the most important, powerful lobbyists. You're more powerful. Because you have men and women, you probably have something like 75, 80 percent of the country believing. But you don't use your power. You don't use your power."

In eight sentences Mr. Trump mentioned some variation of power six times, to a group of individuals who have professed their love and loyalty to Jesus, who in his most famous sermon declared, "Blessed are the poor in spirit" and "Blessed are the meek," who said, "My strength is made perfect in weakness," and who was humiliated and crucified by the powerful.

To better understand Mr. Trump's approach to life, ethics and politics, we should not look to Christ but to Friedrich Nietzsche, who was repulsed by Christianity and Christ. "What is good?" Nietzsche asks in "The Anti-Christ": "Whatever augments the feeling of power, the will to power, power itself in man. What is evil? Whatever springs from weakness. What is happiness? The feeling that power increases -- that resistance is overcome."

Whether or not he has read a word of Nietzsche (I'm guessing not), Mr. Trump embodies a Nietzschean morality rather than a Christian one. It is characterized by indifference to objective truth (there are no facts, only interpretations), the repudiation of Christian concern for the poor and the weak, and disdain for the powerless. It celebrates the "Übermensch," or Superman, who rejects Christian morality in favor of his own. For Nietzsche, strength was intrinsically good and weakness was intrinsically bad. So, too, for Donald Trump.

Those who believe this is merely reductionism should consider the words of Jesus: Do you have eyes but fail to see and ears but fail to hear? Mr. Trump's entire approach to politics rests on dehumanization. If you disagree with him or oppose him, you are not merely wrong. You are worthless, stripped of dignity, the object of derision. This attitude is central to who Mr. Trump is and explains why it pervades and guides his campaign. If he is elected president, that might-makes-right perspective would infect his entire administration.

All of this is important because of what it says about Mr. Trump as a prospective president. But it is also revealing for what it says about Christians who now testify on his behalf (there are plenty who don't). The calling of Christians is to be "salt and light" to the world, to model a philosophy that defends human dignity, and to welcome the stranger in our midst. It is to stand for justice, dispense grace and be agents of reconciliation in a broken world. And it is to take seriously the words of the prophet Micah, "And what does the Lord require of you but to do justly, and to love kindness and mercy, and to humble yourself and walk humbly with your God?"

Evangelical Christians who are enthusiastically supporting Donald Trump are signaling, even if unintentionally, that this calling has no place in politics and that Christians bring nothing distinctive to it -- that their past moral proclamations were all for show and that power is the name of the game.

The French philosopher and theologian Jacques Ellul wrote: "Politics is the church's worst problem. It is her constant temptation, the occasion of her greatest disasters, the trap continually set for her by the prince of this world." In rallying round Mr. Trump, evangelicals have walked into the trap. The rest of the world sees it. Why don't they?

Peter Wehner, a senior fellow at the Ethics and Public Policy Center, served in the last three Republican administrations and is a contributing opinion writer.