What were the factors that led to United States to follow the policy of
Imperialism?

Explanation:

Economic competition among industrial nations. Political and military competition, including the creation of a strong naval force. A belief in the racial and cultural superiority of people of Anglo-Saxon descent.

a social contract.

"a social contract is an agreement between citizens and their leader where the citizens give up certain freedoms in exchange for protection. the constitution of the united states is an example of a social contract."

newly independent countries of the former ussr