The message of the cartoon is that two of the major policies the US adopted in Vietnam, 'no surrender' and 'vietnamisation,' are incompatible. Nixon's two policies could not co-exist and if he wanted to reach a resolution in Vietnam, he would have to follow just one course of action. Source details to support this include the two horses, one labelled 'no surrender' and the other 'vietnamisation' - they represent the two policies. The horses are seen to be pulling each other apart and running in opposite directions which shows that they cannot work together. Another source detail which supports the message is the fact that Nixon appears to be struggling to control the two horses. I know from my own knowledge that the US did in fact have a 'no surrender' attitude despite attacks from highly trained Viet Cong fighters - as a result approximately 700,000 allied casualties were sustained during the war. Nixon implemented Vietnamisation in 1969 by pulling out US troops but giving financial support to the South Vietnamese army; as this involved removing troops, it can be said to contradict the policy of 'no surrender.'