Bradley Longfield on William Jennings Bryan’s view of the mission of the church:

Bryan did not limit his efforts for moral reform to the Chautauqua circuit alone. In marked contrast to his fellow Presbyterian, J. Gresham Machen, Bryan campaigned tirelessly within the church for social, political, and economic reform. “What is a church for,” he asked in 1909, “if it is not to stand for morality in all things and everywhere?” A prophet of personal and national piety, Bryan manifested unswerving loyalty to the nineteenth-century evangelical heritage that married revivalistic fervor and dedication to social reform. The church could not neglect its calling to christianize America.

Bryan was, in fact, a theologically conservative Social Gospeler. The social agenda that Bryan set before the church included “taxation, trust regulation, labor, the monetary system, peace and disarmament, temperance, anti-imperialism, woman’s suffrage.” “These questions are before us,” Bryan insisted. “They cannot be avoided; they must be settled, and church members must take their part in the settlement; ministers also must have a voice in this work.” Bryan served on the temperance committee of the Federal Council of Churches and the general committee of the Interchurch World Movement. In 1919 he praised the Federal Council of Churches–no group of conservatives–as “the greatest religious organization in our nation,” noting, “It gives expression to the conscience of more than seventeen million members of the various Protestant churches; its possibilities for good are limitless; its responsibilities are commensurate with its opportunities.” Though committed to traditional Christianity, Bryan willingly cooperated with those who differed from him theologically in order to further his crusade to build a Christian nation.

Bryan’s Christian faith and trust in the people buoyed his reforming zeal with an inexhaustible optimism. He believed he was born into “the greatest of all the races” in the “greatest of all lands” during the “greatest of all ages.” In 1911 he itemized the progress that marked his era’s superlative character: “Intelligence and intellectual capacity were increasing; educational standards were rising; moral standards were improving; people were studying ethics as never before; the spirit of brotherhood was abroad in the land; there was more altruism than ever before; the tide was running in favor of democracy; the peace movement was spreading; reason was asserting itself; and moral forces were taking control.” To Bryan only one conclusion was possible: ‘The morning light is breaking. Day is at hand.”

The advent of the World War beclouded Bryan’s sunny forecast. The horror of Christians slaughtering one another with the blessing of their Christian nations damaged but did not destroy the Commoner’s faith. Christian civilization hid gone mad; Bryan set out to determine cause of its disease.

In “The Prince of Peace” Bryan had warned against the consequences of Darwinism but moderately allowed, “While I do not except the Darwinian theory I shall not quarrel with you about it; I only referred to it to remind you that it does not solve the mystery of life or explain human progress.” The war impelled Brian to reevaluate Darwiniansim as a possible cause of the hostilities.

The Presbyterian Controversy, pages 66 and 67.