In the u. s., each branch of the government has its own responsibilities and at the same time they work together to make the country run smoothly. which term describes this idea?

I believe it is called "Check and Balances" but feel free to search it up and see whether it matches what you are looking for.

Protecting and assisting  u.s. citizens  living or traveling abroad; assisting u.s.  businesses  in the international marketplace; coordinating and providing support for international activities of other u.s. agencies (local, state, or federal government), official visits overseas and at home, and other diplomatic efforts.keeping the public informed about u.s. foreign policy and relations with other countries and providing feedback from the public to administration officials.providing  automobile registration  for non-diplomatic staff vehicles and the vehicles of diplomats of foreign countries having  diplomatic immunity  in the united states