Answer:
One of the key reason why the war in Vietnam became increasingly unpopular in America was the US atrocities televised on American TV. Therefore, the war became increasingly unpopular as 71 % of American citizens at home thought the war was a mistake and 58% thought it was immoral which made it unpopular.
Another major reason why the war became increasingly unpopular in America was the cost of the war. It costed the US $ 400,000 for every Vietcong dead. The US spent a lot of money between $20 to $30 billion on the Vietnam.