Propaganda in the form of posters were widely used during both World War 1 and 2 on the American home front. These propaganda pieces were used to generate support on the home front, motivate people to enlist and promote the wars as being justified in both legal & moral terms. Many famous ones exist like the Uncle Sam "I Want You" poster or the iconic "We Can Do It".
For some reason, these World War propaganda pieces were never used widely if at all during the Vietnam era. Most propaganda by the US gov't involved secrecy and censorship.
Let's say just before military forces land in Vietnam or in the early days of the conflict, the US gov't re-issues the World War 1 and 2 posters with updated words (replacing references to Germany or Japan with Vietnam or Communism), commissions new art from illustrators & cartoonists and does mass distribution of these. Posters of Uncle Sam telling people to enlist in the military, encouraging to buy war bonds, depicting Ho Chi Minh as a sinister villain much like Hitler, Tojo or Mussolini...that sort of stuff.
Would this succeed? Would public support be galvanized? Would it keep said support going? How would this WW1/2 era propaganda sit with the anti-war movement?