Which chamber of Congress has the power to approve treaties?

The Senate has the power to approve treaties because, as outlined in Article II, Section 2 of the U.S. Constitution, the President has the authority to negotiate treaties with foreign nations, but these treaties must be ratified by a two-thirds majority of the Senate to become effective. This requirement is part of the checks and balances established in the Constitution, ensuring that both the executive branch (the President) and the legislative branch (the Senate) are involved in the treaty-making process, thereby preventing any single branch from having unilateral control over foreign policy.

The other options do not have the constitutional authority to approve treaties. The House of Representatives is not involved in treaty ratification; instead, it has specific roles related to revenue and budget. The Supreme Court, while an important part of the judicial system, does not engage in treaty approval but may interpret treaties as they pertain to legal cases. The Executive Council is not a recognized entity within the framework of the U.S. Constitution regarding foreign affairs or treaty-making.