The Tet Offensive affected perceptions of the Vietnam War withing the United States because option C. Americans grew critical of the war because the Viet Cong were viewed as remaining strong. The Tet Offensive came during the New Year's holiday called Tet. It was launched by the Viet Cong and South Vietnam. There were a lot of protests and marches against the war in America. There were strong feelings against the war and the Viet Cong was seen as still strong.