Answer
Hi, a strong thesis in this topic could be;
The Vietnam War shaped Modern World History, though it was caused by the American passion to end communism which affected their social, economical and political lives.
Step-by-step explanation
The Thesis statement is a sentence that captures the main ideas reflected in a paper. It is normally one or two sentences that tell the readers what the paper is about and aids the writer in keeping the argument focused. In this case, the thesis can be developed by background information on the Vietnam War, two paragraphs on major causes of the war, two paragraphs on the major consequences of the war, three paragraphs on solutions to the war and lastly three paragraphs on importance of the war on modern world history.