"Heathcliffe" -- It was President Truman who started supplying arms and supplies to France during the First Indochina War (War of Independence 1946-1954). This was done under the "Marshall Plan:. It included military supplies along with aircraft plus military pilots flying supply missions from 1948 onwards and flying combat missions from 1949 onwards.
Eisenhower only continued what Truman started.
The "National Liberation Front of Southern Vietnam" (NLF), which most people inaccurately call the Viet Cong, was not established until December 1959. What the French were fighting was the "Peoples Army of Vietnam" (PAVN) which the American OSS (forerunner of the CIA) had helped establish along with arming and training in 1944 to fight the Japanese and Vichy French. The nationalist political arm was called the Viet Minh.
The reason that Truman aided the French was that the US was paranoid about the spread of countries with socialist governments and employed the policy of "containment". In the view of Americans, no country may be "neutral" but is either anti-communist or pro-communist.
A former TV news cameraman and journalist with over 30 years in the industry in Australia and Southeast Asia, including as a War Correspondent during the Second Indochina (Vietnam) War.
Currently a SE Asian historian.