The Constitution gives the President most of the responsibility for FOREIGN POLICY.
The president of the United States is the head of State and Government of the United States. It is the highest political office in the country by influence and recognition. The president leads the executive branch of the federal government.
Among other powers and responsibilities, Article II of the Constitution of the United States entrusts to the president the "faithful execution" of the federal law, makes the president the commander-in-chief of the Armed Forces, authorizes him to appoint executive and judicial officers with the advice and consent of the Senate places it at the forefront of the foreign policy of the United States, and allows the president to grant pardons.
About foreign policy, the president negotiates treaties with foreign nations. He is also the Commander in Chief of the armed forces, and as such has broad authority over them, once they are deployed. The Secretary of State is the Minister of Foreign Affairs of the United States and is the primary conductor of international diplomacy.