What is the official name for sharing power
between the national government and the
states in the American system of government?

Limited government
Checks and Balances
Separation of powers
Federalism

answer is b.

  it is always the best policy to have good communication and good relations between individuals and, specially, between leaders of the countries. for this purpose, among others, there is a common place, the united nations, where the representants can present his and learn about the other country's policies.