The editor of The Atlantic from 1909 to 1938 called on the United States to abandon its neutrality and enter the war “purely for a world idea.”

U.S. marines pose for the corps's recruiting campaign in 1918. Before America entered the war, the size of its army ranked just 17th in the world. By the war's end, the U.S. military had grown more than 100-fold. (National Archives)

The war has brought America great prosperity. Some hundreds of our citizens have gained great fortunes, some thousands have two dollars to spend where once one sufficed. A hundred millions of us, it is true, have to pay half as much again for the necessities of life. But the sense of money is everywhere. The papers teem with the printed billions of the stock market, and editors flatter their readers with the massive figures of our export trade. This prosperity is neither our fault nor our merit. It arises from circumstances which give us, as a people, acute unhappiness. Not unnaturally, the contrast between the misery of Europe and the overflowing garners of America wins for us foreign envy and dislike. Not unnaturally, it rouses repugnance in the breasts of many onlookers at home. It is not nice to batten on suffering surpassing all the horror which the civilized world has known. It is not nice, and, though the situation is not of our own making, it is not comfortable.

But comfortable or not, the situation has been a test of character. England was driven to make her great decision within three days, while we for almost as many years have been left to find ourselves, swayed by fresh argument, now forward, now back …

But when the rape of Belgium came, our sympathies were fixed. The Lusitania massacre, the butcheries of Armenia, and organized piracy on the high seas made our judgment certain. It was not the cause but the method of the war which made our assurance sure. To Americans, a Teuton victory could only mean in Europe the subversion of everlasting right.

And, as the nation felt, so felt the leader. Trained in English thought, with British blood flowing through him, his mind and spirit disciplined by Burke and Wordsworth, every consideration of birth and education urged him to sympathize with the Allies. But Mr. Wilson was president of the greatest neutral nation. He shared to the full the common American belief that the world can no longer progress except through peace. And the United States, a world in miniature where the nations have joined together as a single people in a supreme experiment in the art of living together, can alone provide a common clearinghouse for the discussion of a worldwide pact. As spokesman for America, the president kept the peace and offered, in all sincerity, his offices to the belligerents …

Scarcely had the reverberation of that celebrated speech died down when we began to perceive, even the traditionalists among us, that the time when the United States must cease to be neutral was not in the next war, but now

In a war involving the nations of five continents, the United States alone fights without expectation, without desire for reward other than the common security of the seven seas. For herself alone she demands absolutely nothing. She enters the struggle purely for a world idea. France, most heroic of nations, fights for her life; Russia for power; Italy and Roumania for territory; unhappy Serbia and Belgium because their rights as nations are destroyed; England because her empire, even her existence, is at stake; the Central Powers, from a coarse mingling of fear and greed; but if we fight, we fight because a world ordered like this one is intolerable to all, remote and near. In such a world, security, liberty, and the pursuit of happiness are forever impossible.