The "Fourth Campaign" refers to a significant military operation conducted during the Vietnam War. It took place in 1968 and was part of a series of offensives aimed at weakening the South Vietnamese government and its allies, including the United States. This campaign involved coordinated attacks by the North Vietnamese Army and the Viet Cong across various regions in South Vietnam. The Fourth Campaign is notable for its intensity and the strategic surprise it created, particularly during the Tet Offensive. This offensive marked a turning point in public perception of the war, as it demonstrated the resilience and capability of the communist forces, despite heavy casualties on both sides.