Who serves as the President of the Senate?

The Vice President of the United States serves as the President of the Senate. This role is established in the Constitution, which designates the Vice President as the official leader of the Senate. The Vice President's primary responsibility in this capacity is to preside over Senate sessions and maintain order. While they also have the ability to cast a vote in the event of a tie, the Vice President typically does not engage in the day-to-day legislative activities, as that role is usually fulfilled by the President pro tempore or other Senate leaders.

In this context, other roles such as the Speaker of the House, Chief Justice, and Secretary of State do not pertain to the leadership of the Senate. The Speaker of the House leads the House of Representatives, while the Chief Justice presides over court proceedings and the Secretary of State handles foreign affairs. Therefore, the correct choice aligns perfectly with the established constitutional framework regarding the Senate's leadership.