The Vietnam War began as a conflict between North and South Vietnam following their division in 1954. The U.S. initially sent advisors and then troops to support South Vietnam against communist North Vietnam and Viet Cong forces. Despite massive U.S. bombing and troop deployments, the Tet Offensive in 1968 showed the war was not going well. Growing domestic opposition led to U.S. withdrawal under Nixon and the fall of South Vietnam to communist forces in 1975. The human and financial costs for the U.S. and Vietnam were immense. The war left deep scars and lessons about the difficulties of asymmetric warfare.