Which body must approve international treaties negotiated by the President?

The body that must approve international treaties negotiated by the President is the Senate. This requirement is established in the U.S. Constitution, specifically in Article II, Section 2, which states that the President shall have the power to make treaties, provided that two-thirds of the Senate present concurs. This significant check on the executive power ensures that treaties reflect broader consensus rather than being solely based on the President's decisions. This role of the Senate in treaty approval highlights the importance of collaboration between branches of government, maintaining a balance of power and preventing unilateral decisions by the executive branch.

Other options are not involved in the treaty approval process. The House of Representatives does not have a direct role in this specific aspect of international relations, while the Supreme Court focuses on judicial review and interpretation of laws rather than treaty approval. The Cabinet consists of the heads of the executive departments and serves as advisors to the President but does not engage in the treaty ratification process.