The US Constitution divides the powers of foreign relations between the executive and legislative branches, granting some powers exclusively to the president and others to Congress. Foreign policy experts say that presidents have accumulated power at the expense of Congress in recent years, as part of a pattern in which, in times of war or national emergency, the executive branch tends to eclipse the legislative branch. This periodic tug-of-war between the president and Congress over foreign policy is not a by-product of the Constitution, but rather one of its main objectives. Article I of the Constitution lists several of the powers of Congress in matters of foreign affairs, including those of “regulating trade with foreign nations,” declaring war, “forming and supporting armies,” providing and maintaining a navy, and “establishing rules for the government and regulation of land and naval forces.” The Constitution also makes two of the president's foreign affairs powers dependent on Senate approval: treaties and the appointment of diplomats.
Congress also plays an oversight role through the annual appropriations process, allowing congressional committees to review in detail the budgets and programs of vast military and diplomatic bureaucracies. The president's authority in foreign affairs is based on Article II of the Constitution. The statute gives the incumbent the powers to conclude treaties and appoint ambassadors with the advice and consent of the Senate (treaties require the approval of two-thirds of the senators present). Appointments require the consent of a simple majority. From this language emerges a wide range of associated or “implicit” powers.
For example, the explicit power to appoint and receive ambassadors derives the implicit authority to recognize foreign governments and to carry out diplomatic activities with other countries in general. From the commander-in-chief clause, the powers to use military force and gather foreign information are derived. Presidents also resort to statutory authorities. Congress has passed a law that gives the executive additional authority to act on specific foreign policy issues. For example, the International Emergency Economic Powers Act (197) authorizes the president to impose economic sanctions on foreign entities. Presidents also cite case law to support their claims to authority.
Curtiss-Wright Export Corporation (193) and Youngstown Sheet & Tube Company v. In the first, the court held that President Franklin D. Roosevelt acted within his constitutional authority when he filed charges against the Curtiss-Wright Export Corporation for selling arms to Paraguay and Bolivia in violation of federal law. Lawyers for the executive branch often cite Judge George Sutherland's broad interpretation of the president's powers in matters of foreign affairs in that case. The president is “the only body of the federal government in the field of international relations,” he wrote on behalf of the court. Congress can also use its “purchasing power” to curb presidential military ambitions, but legislators don't usually take action until near the end of a conflict.
In addition, legislators are often reluctant to have their constituents see them as an obstacle to US funding. During Obama's administration senior officials from US military commanders said that while well-intentioned restrictions on US aid complicated other foreign policy objectives such as fighting terrorism or fighting narcotics. Congress began claiming a greater role in intelligence oversight in 1970s particularly after Church Committee discovered privacy abuses committed by CIA FBI & NSA Congress passed several laws regulating collection intelligence information & established committees overseeing activities executive branch areas such covert operations. Many presidents have protested these events & have stated that Congress was invading their prerogatives Senate has passed more than 1 600 treaties over years but has also rejected or refused consider many agreements After World War I senators became famous for rejecting Treaty Versailles which had been negotiated President Woodrow Wilson More recently small coalition upper house blocked ratification United Nations Convention Law Sea despite support RepublicanThe periodic tug-of-war between presidents and Congress over foreign policy is not a by-product of our Constitution but rather one its main objectives. The drafters distributed political power and imposed checks and balances to avoid monarchical tyranny while also seeking to remedy deficiencies from our national charter adopted in 1777. Article I lists several powers granted to Congress while Article II grants some exclusively to presidents. Through statutory authorities, case law, and congressional oversight through appropriations processes, both branches have sought to shape US foreign policy.