Anti-war movement
History: 

American Revolutionary War: Substantial opposition to British war intervention in America led the British House of Commons on 27 February 1783 to vote against further war in America, paving the way for the Second Rockingham ministry and the Peace of Paris.

Antebellum United States: Substantial antiwar sentiment developed in the United States roughly between the end of the War of 1812 and the commencement of the Civil War in what is called the Antebellum era. A similar movement developed in England during the same period. The movement reflected both strict pacifist and more moderate non-interventionist positions. Many prominent intellectuals of the time, including Ralph Waldo Emerson, Henry David Thoreau (see Civil Disobedience) and William Ellery Channing contributed literary works against war. Other names associated with the movement include William Ladd, Noah Worcester, Thomas Cogswell Upham, and Asa Mahan. Many peace societies were formed throughout the United States, the most prominent of which being the American Peace Society. Numerous periodicals (such as The Advocate of Peace) and books were also produced.  The Book of Peace, an anthology produced by the American Peace Society in 1845, must surely rank as one of the most remarkable works of antiwar literature ever produced.
A recurring theme in this movement was the call for the establishment of an international court to adjudicate disputes between nations. Another distinct feature of antebellum antiwar literature was the emphasis on how war contributed to a moral decline and brutalization of society in general.

American Civil War: A key event in the early history of the modern anti-war stance in literature and society was the American Civil War, where it culminated in the candidacy of George B. McClellan for US president as a Peace Democrat against incumbent President Abraham Lincoln. The outlines of the antiwar stance are seen: the argument of the costs of maintaining the present conflict not being worth the gains that can be made, the appeal to end the horrors of war, and the argument of war being waged for the profit of particular interests. During the war, the New York Draft Riots were started as violent protests against Lincoln's Enrollment Act of Conscription to draft men to fight in the war. The outrage over conscription was augmented by the ability to "buy" one's way out, which could be afforded only by the wealthy. After the war, The Red Badge of Courage described the chaos and sense of death which resulted from the changing style of combat: away from the set engagement, and towards two armies engaging in continuous battle over a wide area.

Second Boer War: William Thomas Stead formed an organization against the Second Boer War, the Stop the War Committee.

World War I: In Britain, in 1914, the Public Schools Officers' Training Corps annual camp was held at Tidworth Camp, near Salisbury Plain. Head of the British Army Lord Kitchener was to review the cadets, but the immenence of the war prevented him. General Horace Smith-Dorrien was sent instead. He surprised the two-or-three thousand cadets by declaring (in the words of Donald Christopher Smith, a Bermudian cadet who was present) "that war should be avoided at almost any cost, that war would solve nothing, that the whole of Europe and more besides would be reduced to ruin, and that the loss of life would be so large that whole populations would be decimated. In our ignorance I, and many of us, felt almost ashamed of a British General who uttered such depressing and unpatriotic sentiments, but during the next four years, those of us who survived the holocaust-probably not more than one-quarter of us – learned how right the General's prognosis was and how courageous he had been to utter it." Having voiced these sentiments did not hinder Smith-Dorrien's career, or prevent him from carrying out his duty in the First World War to the best of his abilities.
With the increasing mechanization of war, opposition to its horrors grew, particularly in the wake of the First World War. European avant-garde cultural movements such as Dada were explicitly anti-war.
The Espionage Act of 1917 and the Sedition Act of 1918 gave the American authorities the right to close newspapers and jailed individuals for having anti-war views.
On 16 June 1918, Eugene V. Debs made an anti-war speech and was arrested under the Espionage Act of 1917. He was convicted, sentenced to serve ten years in prison, but President Warren G. Harding commuted his sentence on 25 December 1921.

Between the World Wars: In 1924, Ernst Friedrich published Krieg dem Krieg! (War Against War!): an album of photographs drawn from German military and medical archives from the first world war. In Regarding the Pain of Others Sontag describes the book as "photography as shock therapy" that was designed to "horrify and demoralize".
It was in the 1930s that the Western anti-war movement took shape, to which the political and organizational roots of most of the existing movement can be traced.  Characteristics of the anti-war movement included opposition to the corporate interests perceived as benefiting from war, to the status quo which was trading the lives of the young for the comforts of those who are older, the concept that those who were drafted were from poor families and would be fighting a war in place of privileged individuals who were able to avoid the draft and military service, and to the lack of input in decision making that those who would die in the conflict would have in deciding to engage in it.
In 1933, the Oxford Union resolved in its Oxford Pledge, "That this House will in no circumstances fight for its King and Country."
Many war veterans, including US General Smedley Butler, spoke out against wars and war profiteering on their return to civilian life.
Veterans were still extremely cynical about the motivations for entering World War I, but many were willing to fight later in the Spanish Civil War, indicating that pacifism was not always the motivation. These trends were depicted in novels such as All Quiet on the Western Front, For Whom the Bell Tolls and Johnny Got His Gun.

World War II: Opposition to World War II was most vocal during its early period, and stronger still before it started while appeasement and isolationism were considered viable diplomatic options.  Communist-led organizations, including veterans of the Spanish Civil War, opposed the war during the period starting with the Molotov–Ribbentrop pact but then turned into hawks after Germany invaded the Soviet Union.
The war seemed, for a time, to set anti-war movements at a distinct social disadvantage; very few, mostly ardent pacifists, continued to argue against the war and its results at the time. However, the Cold War followed with the post-war realignment, and the opposition resumed.  The grim realities of modern combat, and the nature of mechanized society ensured that the anti-war viewpoint found presentation in Catch-22, Slaughterhouse-Five and The Tin Drum. This sentiment grew in strength as the Cold War seemed to present the situation of an unending series of conflicts, which were fought at terrible cost to the younger generations.

Vietnam War: Organized opposition to U.S. involvement in the Vietnam War began slowly and in small numbers in 1964 on various college campuses in the United States and quickly as the war grew deadlier. In 1967 a coalition of antiwar activists formed the National Mobilization Committee to End the War in Vietnam which organized several large anti-war demonstrations between the late 1960s and 1972. Counter-cultural songs, organizations, plays and other literary works encouraged a spirit of nonconformism, peace, and anti-establishmentarianism. This anti-war sentiment developed during a time of unprecedented student activism and right on the heels of the Civil Rights Movement, and was reinforced in numbers by the demographically significant baby boomers. It quickly grew to include a wide and varied cross-section of Americans from all walks of life. The anti-Vietnam war movement is often considered to have been a major factor affecting America's involvement in the war itself. Many Vietnam veterans, including future Secretary of State and U.S. Senator John Kerry and disabled veteran Ron Kovic, spoke out against the Vietnam War on their return to the United States.
Mrs. Ngo Ba Thanh, a Vietnamese peace activist, aligned her Vietnamese Women's Movement for the Right to Live with international activists of the Women's International League for Peace and Freedom (WILPF) and Women Strike for Peace. Her imprisonment and publications about the war brought international attention to the social and economic issues created by the war and fostered international opposition to it.: 109–110 : 85, 89–90  Her arrest and lack of a trial sparked Bella Abzug and WILPF members to write to the United States Congress and petition President Richard Nixon to appeal to South Vietnamese officials for her release,: 126 : 90  which was widely covered in the press. Campaigns opposing the war and conscription also took place in Australia.

South African Border War: Opposition to the South African Border War spread to a general resistance to the apartheid military. Organizations such as the End Conscription Campaign and Committee on South African War Resisters, were set up. Many opposed the war at this time.

Yugoslav Wars: Following the rise of nationalism and political tensions after Slobodan Milošević came to power, as well as the outbreaks of the Yugoslav Wars, numerous anti-war movements developed in Serbia.