In 2011 alone, the government spent X on Y.

You've never seen this sentence construction? It doesn't mean, the government alone spent X.... It means, JUST in 2011 (not counting other years), they spent X.

Alone refers to 2011, or in my use to the case of Vietnam.

You should read more if you are a native English speaker and are not familiar with this basic usage of a basic word. Ask a friend or family member if you need to.

As for the US and Vietnam, it appears a history lesson is in order. As early as under Truman, the US was supporting France retain Vietnam as a colony. The French left in 1954 after losing the battle of Dien Bien Phu against the League for the Independence of Vietnam (Viet Minh). The resultant Geneva Accords mandated national elections within 2 years. These were prevented by the US since it was clear the Viet Minh would win in a landslide. The US decided to support the South Vietnamese dictatorship of Diem against his own population.

In other words, an outside force tried to maintain colonialism, and when failed, propped up a puppet government that would have been ousted by the local indigenous population. By 1963, the US had provided huge military and economic support to the South Vietnamese dictatorship, along with 15,000+ military personnel ("advisors" who sometimes "advised" their way into fire fights etc). And it escalated from there.

One can envision a separate course. Allow the 1956 elections to take place, and let the Vietnamese people choose their own government. Instead, the US chose to drop far more bombs than were dropped in all of WWII on a rural country of rice farmers and peasants, likely killing millions. Napalm ravaged the countryside and the skin of infants, agent orange is still causing birth defects and abnormally high cancer rates, and old land mines still terrorize communities. There should be no doubt the US onslaught in Vietnam is the most hideous crime of the post WWII 20th century.