South Vietnam did not win the Vietnam War because they could not win the Vietnam War. Even with the $168 billion the United States gave the South in weapons, training, supplies, and machinery, hoping to prevent communism, neither the United States nor South Vietnam had the zeal it took to prevent North Vietnam.
South Vietnam also had a corrupt government. Ngo Dinh Diem was the United States' choice as a leader of Vietnam due to his strong anti-communist views; however, he was not necessarily the choice of the South Vietnamese people. In an ironic election to establish a republic, the United States assisted in rigging an election so that Diem would receive 98% of the votes (a suspiciously high number for an election rig, but corruption has no limits). Office of the Historian , "Given the high rate of illiteracy, the hundreds of tiny villages without communication facilities... it is difficult to believe that nearly 98% of the eligible population actually cast votes". Then, Diem, the newly found dictator, started to persecute the Buddhists of a country that was primarily Buddhist, favoring the Catholic minority. Before the war, a communist group, the Vietminh, wanted Ho Chi Minh as a leader and others support Ngo Dinh Diem; however, much of the South was very unhappy under DIeh's rule. Eventually, war broke out between the North and the South. Diem’s army lacked morale; most did not want to fight for him, and some even wanted the North to win. There was even a communist group in South Vietnam active in opposition to Ngo Dinh Diem, according to BBC , "From 1958 onwards, the South came under increasing attacks from communists in South Vietnam itself. They were called the National Liberation Front (NLF)" . In 1963, when Diem was overthrown, the government only became even more unstable. Now, many of the soldiers of South Vietnam were loyal and fighting for survival, but were poorly trained, supplied, and under poor leadership-- whereas the Vietcong of North Vietnam was stronger and had a more organized leadership.
North Vietnam was determined to win and was more unified on a shared goal: to reunify Vietnam as a communist nation. Political propaganda fostered this unity by motivating even poor villagers to oppose the United States and South Vietnam. According to the Army Heritage Center Foundation, the North Vietnamese's clear and established plan included: “cripple South Vietnam’s morale, destroy their will to fight, and incite the people to rise up against their government. At the same time, they wanted to weaken American trust in the South Vietnamese government and discredit U.S. claims of progress.” Support from communist allies such as the Soviet Union and China contributed resources, but their $1.1 billion in aid paled in comparison to the $168 billion given by the U.S. However, this disparity shows that money was less critical than morale, training, and leadership. North Vietnam’s effective guerrilla warfare further enabled its forces to outlast South Vietnam and the United States, which lacked the willpower for a prolonged and seemingly hopeless land war.
The United States drained money on a cause that was not even fully supported by the people and soldiers. At first, the soldiers could not keep up with the guerrilla warfare of the South, but after a win at the Tet Offensive for South Vietnam and the United States, the U.S. realized how large the scale of the attacks had to be for a victory, demonstrating the strength of North Vietnam. Also, after the brutal battle of the Tet Offensive, the U.S. citizens fighting and watching the war from home stopped supporting the war, ultimately leaving the United States to withdraw and wonder why they were ever fighting. According to The Atlantic: “More than 58,000 Americans and as many as 3 million Vietnamese had died in the conflict. America’s illusions of invincibility had been shattered, its moral confidence shaken." The American people lost the will to fight in the Vietnam War and lost trust in the government that drafted its own citizens for another nation.
North Vietnam was unified for support of the war under a shared ideology of communism with the Soviet Union and China. South Vietnam was divided under corrupt leadership, and Americans were dying for a cause they did not believe in. The Vietnam War showed that war is not always about economics, allies, and the size of the military, but sometimes comes down to belief in a cause, unity, direction, and strategy, as demonstrated by the victory of North Vietnam.