A more thorough explanation:

Foreign relations refer to the laws and regulations that govern the relationships between the United States and other countries. It includes both international law, which outlines the rights and obligations of states and international organizations, and domestic law that affects foreign relations.

The President of the United States has the power to appoint ambassadors and other public ministers and consuls, who act with binding authority to represent the country in foreign affairs. Consuls are officers commissioned by the government to represent it in a foreign country and protect the interests of its citizens.

While states are not sovereign under international law, they can prescribe and enforce rules of law that affect foreign relations, unless the Constitution vests exclusive jurisdiction in the Federal Government. For example, foreign nationals present in the United States are subject to state law, which can have important consequences for U.S. foreign relations.

International law overlaps with foreign relations law to the extent that the domestic law of the United States includes rules giving effect to rules of international law, but does not cover the same subject matter. The law of the United States determines the conduct of its foreign relations without reference to any international rule in many areas.

• The President of the United States appoints ambassadors and other public ministers and consuls to represent the country in foreign affairs.
• Consuls are officers commissioned by the government to represent it in a foreign country and protect the interests of its citizens.
• States can prescribe and enforce rules of law that affect foreign relations, unless the Constitution vests exclusive jurisdiction in the Federal Government.
• Foreign nationals present in the United States are subject to state law, which can have important consequences for U.S. foreign relations.

These examples illustrate how foreign relations law affects the relationships between the United States and other countries. The President's appointment of ambassadors and consuls, as well as the ability of states to prescribe and enforce rules of law, are important aspects of foreign relations. The impact of state law on foreign nationals also highlights the interconnectedness of domestic and international law in foreign relations.