The State Department is the United States government's lead agency for foreign affairs. It manages diplomatic relations with foreign governments, represents U.S. interests at the United Nations and other international bodies, negotiates treaties and international agreements, and coordinates the country's response to global crises, from wars to pandemics to natural disasters.

Day to day, the department runs the U.S. Foreign Service, the roughly 13,000 diplomats who staff embassies and consulates in more than 170 countries. Ambassadors, who serve as the president's personal representative in each country, report through the State Department chain of command up to the Secretary of State, who is the president's principal foreign policy adviser.

The department also performs services that touch millions of ordinary Americans directly. It issues U.S. passports, provides emergency assistance to American citizens in trouble abroad, adjudicates visa applications for foreign travelers and immigrants, and administers educational exchange programs like the Fulbright Program.