(edited and abbreviated)
There has never been a just one, never an honorable one on the part of the instigators of war. I can see a million years ahead, and this rule will never change. The handful in power, as usual, will shout for the war. The pulpit will warily and cautiously object at first; the great, big, dull bulk of the nation will rub its sleepy eyes and try to make out why there should be a war, and will say, earnestly and indignantly, "It is unjust and dishonorable, and there is no necessity for it." Then the handful will shout louder.
A few fair men will argue and reason against the war with speech and pen, and at first will have a hearing and be applauded; but it will not last long; those others will outshout them, and presently the anti-war audiences will thin out and lose popularity.
And now the whole nation, pulpit and all, will take up the war-cry, and shout itself hoarse, and mob any honest man who ventures to open his mouth; and presently such mouths will cease to open.
Next the statesmen will invent cheap lies, putting the blame upon the nation that is being attacked, and every man will be glad of those conscience-soothing falsities, and he will by and by convince himself that the war is just, and will thank God for the better sleep he enjoys after this process of grotesque self-deception.
Mark Twain (1835-1910), was a popular American writer, humorist and satirist, with a keen wit. Twain is perhaps most noted for his novel Adventures of Huckleberry Finn (published in 1884), which deals with overcoming the entrenched racism of the time.
[See also: A poem by Walt Whitman, and Siegfried Sassoon's Aftermath]
[Related: a Theodore Roosevelt quote]