From Wikipedia

Vietnam War Unclassified

Opposition to United States involvement in the Vietnam War is significant because it was the first time a war was shown and accessed through the media to the public in the United States.

First protests against U.S. involvement in Vietnam take place in 1945, when United States Merchant Marine sailors condemn the U.S. government for the use of U.S. merchant ships to transport French troops whose express purpose is to "subjugate the native population" of Vietnam. These protesters oppose the "recolonization" of Vietnam, though they lack the understanding of increasing polarization of the north and south. The Vietminh were committing many atrocities against its own people, the US failed to act at this critical juncture.