He painted Goldwater as a warmonger, remember the famous nuclear bomb ad with the child picking flower pedals? Woodrow Wilson ran his reelection on the slogan "he kept us out of war", only to commit troops to Europe. FDR vowed to not get into WWII, Nixon won promising a "secret" plan to get out of Vietnam, Obama promised to get out of Afghanistan and Iraq. All these presidents promise to be anti war, until they get elected. I don't know what Kennedy would have done, but putting ground troops in Vietnam was a huge mistake.