Areas of Conflict National government vs. State government

The idea of manifest destiny simply stated it was america's destiny to expand from the atlantic ocean to the pacific. the word "destiny" implies an idea that it was within our rights as a nation to expand. in a paragraph of 125+ words, explain what could be wrong with that idea.

After world war ii, many japanese territories were increasingly difficult for japan to control. placed under the control of other nations. granted independence from japan. supportive of the us occupation.

What was one major cause of worldwide conflict during the first decade of the 21st century?