"The war to end war" (sometimes called "The war to end all wars") was a term used to describe World War I. Originally idealistic, it is now used mainly in a disparaging way.
During August 1914, immediately after the outbreak of the war, British author and social commentator H. G. Wells published a number of articles in the London newspapers which 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, "the war to end war", in In the Fourth Year (1918), where 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 war.
In later years, the term became associated with Woodrow Wilson, despite the fact that Wilson only used it 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 scepticism; 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. Field-Marshal Earl Wavell said despondently of the Paris Peace Conference: "After the 'war to end war', they seem to have been pretty successful 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 Richard Nixon, in his Silent Majority speech, said, "I do not tell you that the war in Vietnam is the war to end wars".