The United States government establishes and maintains embassies in countries with which it has diplomatic relations. Ambassadors, also known as chiefs of mission, take charge of the embassies, and work to represent and advance the foreign policy goals of the U.S. president and his administration in the host countries. They ensure the security of embassy staff and property, sign trade agreements, manage communications with the Department of State, and serve Americans abroad with professionalism.

Discharging Their Duties

Ambassadors are usually resident, meaning they live in the countries to which they are accredited. In other cases, a resident ambassador may be concurrently accredited to other nations -- usually neighboring ones. This means he will serve as a nonresident ambassador to the neighboring countries and continue living in the country in which he is already a resident ambassador. Ambassadors accredited to international organizations such as the United Nations are also nonresident or ambassadors-at-large, since they are typically based in the U.S.

During their service, ambassadors normally receive instructions or the president’s directives from the secretary of state. Speaking to The Hill, a U.S. political website, Thomas Pickering, former U.S. ambassador to several nations, including Russia and Israel, notes that the President can choose to contact an ambassador directly.

Advancing Foreign Policy

Being the highest-ranking diplomat, an ambassador relays the U.S. foreign policies to the host country’s government. She works with the local leadership to advance American interests. If the U.S. government is keen on fighting global warming, then an ambassador can lobby the country’s legislators to make laws that, for instance, cap carbon emissions. Ambassadors also ensure foreign service officers and other mission staff speak with one voice on all U.S. foreign policy issues.

Protecting Americans Overseas

Ambassadors have a duty to ensure the security of all Americans living in the countries to which they are sent. The ambassadors and their staff monitor security issues in the host country and keep the U.S. secretary of state updated. When necessary, the U.S. can use this information to issue travel advisories to Americans traveling to or living in a specific foreign nation.

Apart from protecting overseas Americans, ambassadors are responsible for the security of mission staff and embassy facilities. They must regularly assess security risks -- especially terrorism -- and request additional security personnel, as well as funding for embassy construction and upgrades from the U.S. government.

Promoting Diplomatic and Economic Ties

America relies on its ambassadors to build and maintain strong diplomatic and economic ties with foreign nations that are of strategic importance. To do this, ambassadors often attend state functions, hold bilateral talks with government officials of the host country to negotiate trade agreements and sign the resulting treaty. When there is diplomatic conflict or a disturbance of international relations, it is the ambassador’s job to lead negotiations with the host government and strive to find a mutually beneficial diplomatic solution.