"The war to end war" (sometimes called "The war to end all wars") was a term for the First World War of 1914–1918. Originally idealistic, it is now used mainly sardonically.
During August 1914, immediately after the outbreak of the war, British author and social commentator H. G. Wells published a number of articles in London newspapers that subsequently appeared as a book entitled The War That Will End War. Wells blamed the Central Powers for the coming of the war and argued that only the defeat of German militarism could bring about an end to war. Wells used the shorter form of the phrase, "the war to end war", in In the Fourth Year (1918), in which he noted that the phrase had "got into circulation" in the second half of 1914. In fact, it had become one of the most common catchphrases of the First World War.
In later years, the term became associated with Woodrow Wilson, despite the fact that Wilson used the phrase only once. Along with the phrase "make the world safe for democracy", it embodied Wilson's conviction that America's entry into the war was necessary to preserve human freedom.
Even during World War I, the phrase met with some degree of skepticism; the British politician David Lloyd George is reputed to have said, "This war, like the next war, is a war to end war." As it became apparent that the war had not succeeded in ending war, the phrase took on a more cynical tone. The British staff officer Archibald Wavell, a future field marshal and viceroy of India, said despondently of the Paris Peace Conference, "After the 'war to end war', they seem to have been in Paris at making the 'Peace to end Peace'." Wells himself used the phrase in an ironic way in the novel The Bulpington of Blup (1932).Walter Lippmann wrote in Newsweek in 1967, "The delusion is that whatever war we are fighting is the war to end war", while President Richard Nixon, in his "Silent Majority" speech, said, "I do not tell you that the war in Vietnam is the war to end wars".