How The U.S. Became Involved In The Politics Of Southeast Asia. How This Involvement Impacted The U.S. Political Climate Of The 1950s?

USA's involvement in Southeast asian politics was mainly because of China's and Russia's involvement in those areas. Both of these super powers were gaining by interfering in those areas and thus USA had to keep check on rivals. Vietnam war was the most popular USA interference in southeast Asia. It was fought mainly for preventing rivals becoming more strong and USA lost much because of that. All the detailed and very to-the-point account of USA's involvement in Southeast Asia is mentioned in detail in link provided below.
Do visit this Detailed but to-the-point article of US involvement in Southeast Asia.

It seems to go back to at least the 1940s and was largely bound up with the fear of communism. The best material I can find on this subject is this lecture.

United States became involved in Southasian politics because of its arch rivals China and Russia. Communism has been considered as a major threat to America. So when China and Russia got involved in SouthAsian politics, America also got involved so that it can keep an eye on these powers. During the 1940's and 1950's, China and Russia played an important role in SouthAsian politics. China siding with Pakistan and Russia siding with India. America was seeing Russia as a strong rival so it supported Pakistan at that time against India. From that time onwards, U.S has been changing sides in South Asia according to its own benefits.

United States became involved in Southasian politics because of its arch rivals China and Russia. Communism has been considered as a major threat to America. So when China and Russia got involved in SouthAsian politics, America also got involved so that it can keep an eye on these powers. During the 1940's and 1950's, China and Russia played an important role in SouthAsian politics. China siding with Pakistan and Russia siding with India. America was seeing Russia as a strong rival so it supported Pakistan at that time against India. From that time onwards, U.S has been changing sides in South Asia according to its own benefits.