The response to the terrorist attacks in London last week suggests something about the soul of Western democracies.

Political leaders in Britain and the United States have repeated their resolve to defeat the strategic threat of radical Islam. Politicians understand the potential to wreak havoc on civilian populations with the world's deadliest weapons. But many religious figures in the West seem reluctant to confront the ambitions of Osama bin Laden and his allies.

Of course, we expect church leaders to offer their prayers and condolences in times of suffering, and such prayers were graciously offered. Yet I can't help thinking that we expect something more: Those who are attentive to things of the spirit should speak, with clarity and force, about the existential threat these attacks represent.

Instead, we hear wishful words of sweetness and light. A coalition of churches in Britain has announced its desire "to grow together in mutual understanding." The World Council of Churches reaffirms its "commitment to building a just and peaceful world." Frank Griswold, bishop of the Episcopal Church in America, says we must "overcome the fears and hatreds that divide us." And Bob Edgar, General Secretary of the National Council of Churches, challenges all religious communities "to pursue peace in a thousand ways."

What does any of this have to do with an enemy sworn to destroying the foundations of civilized life? And where is the moral vision to defeat it?

The problem with many church institutions, especially those in the progressive wing, is that they regard war-any war-as the greatest possible evil. They ignore centuries of Christian teaching about the ethics of war, otherwise known as the just war tradition. It argues that governments may, and sometimes must, wage war to restrain the violence of wicked men. This is Christian realism: the proposition that evil is a fact of human nature and that, in its advanced forms, it will not yield to dialogue and diplomacy.

No one wants ministers to whip their flocks into a self-righteous frenzy. Yet pacifism in the face of radical Islam will not protect innocent lives, and it must not be the chief influence on democratic governments. That was the grievous mistake of churches in the 1930s, and it allowed the Nazis to nearly devour the whole of Europe.

Theologian Reinhold Niebuhr saw this as utopianism-a dreamlike vision of human perfection that denies the unpleasant facts of human existence. Utopians, Niebuhr said, can't distinguish between "the peace of capitulation to tyranny and the peace of the Kingdom of God." The political result, he warned, is to make democracies "weak and irresolute before a resolute and terrible foe."

Prayers for peace are always to be welcomed. Yet so are prayers for courage and strength-the strength to defeat the enemies of peace, of decency, and of humanity itself.

Mr. Loconte is a research fellow in religion at the Heritage Foundation and editor of "The End of Illusions: Religious Leaders Confront Hitler's Gathering Storm" (Rowman & Littlefield). He served as a member of the Congressional Task Force on the United Nations.