What event weakened the government of south Vietnam?

The Tet Offensive in January 1968 significantly weakened the government of South Vietnam. This large-scale surprise attack by North Vietnamese and Viet Cong forces on key cities and military bases exposed the vulnerabilities of the South Vietnamese military and the U.S. strategy in the region. The widespread violence and the subsequent media coverage shifted public opinion in the United States against the war, undermining support for the South Vietnamese government and its leadership. This loss of confidence further destabilized the South Vietnamese regime, leading to increased political turmoil.