What were the causes and impacts of the US expanding its control overseas?

other countys could not take care of there own people

in 550 b.c.e. cyrus the great, the leader of the persians, conquered the medes and united the iranian people under one ruler for the first time. cyrus became the first king of the persian empire and went on to establish one of the largest empires in world.

in the declaration of independence, thomas jefferson announced that every human being has “certain unalienable rights,” among which are those to “life, liberty, and the pursuit of " hope i