"Save America and you save the world." Through immigration the United States is in a unique sense the most foreign country and the greatest mission field on the globe. "All peoples that on earth do dwell" have here their representatives, gathered by a divine ordering within easy reach of the gospel. Through them the world may be reached in turn. Every foreigner converted in America becomes directly or indirectly a missionary agent abroad, spreading knowledge of the truth among his kindred and tribe.[89] The greatness of the opportunity is the measure of obligation. God's message to this nation has been thus interpreted: "Here are all these people; I have taken them from the overcrowded countries where they were living and sent them to you, that you may mass your forces and lend a hand to save them." No such opportunity ever came to a nation before. The Christian church must seize it or sink into deserved decadence and decay. Only a missionary church can save the world or justify its own existence. The manner in which American Christianity deals with the religious problems of immigration will decide what part America is to play in the evangelization of the nations abroad. [Sidenote: The Gospel the Chief Factor] We have now reached the vital part of our subject. We have learned to discriminate between peoples and find the good in all of them. We have seen that assimilation is essential to national soundness and strength. But we have yet to realize that the most potential factor in assimilation is not legislation or education but evangelization. There is no power like the gospel to destroy race antipathies, break down the bars of prejudice, and draw all peoples into unity, brotherhood, and liberty--that spiritual freedom wherewith Christ makes free. When American Protestantism sees in immigration a divine mission none will discover in it thenceforth a human menace. [Sidenote: Shall America be kept Christian] Marvelous mission, involving the destiny of free America. A writer asks, "Will New England be kept Christian?" and answers, "That depends. Population is greatly changing. Immigrants from all parts of the world are here. They will continue to come. Unless they are molded according to the principles of our religion, they will greatly increase the irreligious elements of New England, already too large. There is a religious basis in those who come, but it will require an application of religious agencies to make them truly Christian citizens."[90] Put America in place of New England, and the question and answer will be as pertinent. Shall America be kept Christian? That depends. It depends upon what American Christians do. [Sidenote: Immigrants not Evangelical]