I believe that when the Japanese surrendered at the end of WW2 the French owned the rubber tree plantations in South East Asia. The French were certain that the Northern forces(Communist Russia) were planning to take the plantations indirectly by influencing North Vietnam to separate from South Vietnam. The North Vietnamese were supplied weapons to overtake the south. The French persuaded US. President Truman to leave a small contingent of US. Troops to help protect the French Plantations from being overtaken. In 1958 or 59 the French sold the plantations to Good Year Tire Corp.. Now a US. Corp. being the owners would now have to be protected with more forces. Previous to that President Eisenhower could see a battle brewing so Eisenhower sent advisors & when casualties of US. Troops took place that was the beginning of the escalation of the Viet Nam War.