Final answer:
HoChiMinh was the president of North Vietnam that the United States did not back because he was a socialist and communist anti-imperialist.
Step-by-step explanation:
The President of North Vietnam, whom the United States refrained from supporting due to his socialist and communist anti-imperialist stance, was HoChiMinh.
Serving as the leader of the Communist Party of Vietnam, HoChiMinh held the position of North Vietnam's president from 1954 until his demise in 1969.
The United States' reluctance to back HoChiMinh stemmed from their ideological opposition to communism and apprehensions about its potential expansion in the region.
Given the prevailing Cold War context, where the U.S. and the Soviet Union were engaged in a global ideological conflict.
Washington's aversion to supporting leaders aligned with communist ideologies, such as HoChiMinh, was a manifestation of their broader geopolitical concerns and anti-communist sentiments during that era.