Final answer:
The vice president of the United States serves as the president of the Senate and can cast tie-breaking votes. Over time, the role of the vice president has evolved, with recent vice presidents taking on more substantive and policy-driven responsibilities.
Step-by-step explanation:
The vice president of the United States is also the president of the Senate. This role is significant in that the vice president presides over Senate sessions and, while usually not voting, has the power to cast a tie-breaking vote in the event that the Senate is equally divided on a bill or nomination.
The vice presidency has evolved over time, gaining much more influence in policy and decision-making processes, as depicted by the active roles of recent vice presidents like Joe Biden and Kamala Harris.
These changes reflect the growing importance and responsibilities associated with the vice presidency, as the role is not simply ceremonial but also integral to the legislative process and the functioning of the executive branch.