Lead-in Activities In the 1950's the United States began to send troops to Vietnam.During the following 25 years the war would create some of the strongest tensions in US history. Almost 3 million US men and women were sent thousands of miles to fight for what was a questionable cause.In total,it is estimated that over 2,5 million people on both sides were killed.Lead-in Activities In the 1950's the United States began to send troops to Vietnam. During the following 25 years the war would create some of the strongest tensions in US history. Almost 3 million US men and women were sent thousands of miles to fight for what was a questionable cause. In total, it is estimated that over 2,5 million people on both sides were killed