Answer:
Why did some believe that US expansion was needed to preserve the "American Spirit?" They thought that America would need a strong navy to protect the markets. Also, in Alfred Mahan's book, The Influence of Sea Power Upon History, he says that America's future would rely on gaining new markets abroad.
Explanation:
Forced migration occurs when people's lives, well-being or freedom is endangered. They may have little or no choice but to move. In some cases, such as human trafficking and slavery, people are physically removed from their homes.
I think it is debt from war... hope this helps!