How did Kublai Khan’s empire differ from the Mongol Empire built by Genghis Khan?

Khan’s empire did not expand past ancient China.
Khan’s empire did not conquer China’s capital.
Khan’s empire did not conquer southern China.
Khan’s empire did not unify the Chinese provinces.

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.