a just war: first, any just war must be declared by a lawful authority; second, it must be a just and righteous cause, with sufficient gravity to merit large-scale violence; third, the just belligerent must have rightful intentions – namely, that they seek to advance good and curtail evil; fourth, a just belligerent must have a reasonable chance of success; fifth, the war must be a last resort; and sixth, the ends being sought must be proportional to means being used. Jus in bello (right in war), is the set of ethical rules when conducting war. The two main principles are proportionality and discrimination. Proportionality regards how much force is necessary and morally appropriate to the ends being sought and the injustice suffered. The principle of discrimination determines who are the legitimate targets in a war, and specifically makes a separation between combatants, who it is permissible to kill, and non-combatants, who it is not. Failure to follow these rules can result in the loss of legitimacy for the just-war-belligerent. The just war theory was foundational in the creation of the United Nations and in international law's regulations on legitimate war. Lewis Coser, U.S. conflict theorist and sociologist, argued conflict provides a function and a process whereby a succession of new equilibriums are created. Thus, the struggle of opposing forces, rather than being disruptive, may be a means of balancing and maintaining a social structure or society. Limiting and stopping Religious groups have long formally opposed or sought to limit war as in the Second Vatican Council document Gaudiem et Spes: "Any act of war aimed indiscriminately at the destruction of entire cities of extensive areas along with their population is a crime against God and man himself. It merits unequivocal and unhesitating condemnation." Anti-war movements have existed for every major war in the 20th century, including, most prominently, World War I, World War II, and the Vietnam War. In the 21st century, worldwide anti-war movements occurred in response to the United States invasion of Afghanistan and Iraq. Protests opposing the War in Afghanistan occurred in Europe, Asia, and the United States. Pauses During a war, brief pauses of violence may be called for, and further agreed to ceasefire, temporary cessation, humanitarian pauses and corridors, days of tranquility, de-confliction arrangements. There a number of disadvantages, obstacles and hesitations against implementing such pauses such as a humanitarian corridor. Pauses in conflict