The main constitutional duty of the United States Vice President is to immediately succeed the Presidency in case the President dies, steps down or becomes incapacitated. The Vice President also functions as the U.S. Senate President, tasked to cast the deciding ballot in the event of a draw.
Despite being the presiding officer in the Senate, the Vice President rarely attends Congressional sessions. A senator is usually elected by the Upper House to serve in the Vice President's stead. Aside from those mandated in the Constitution, the Vice President may also assume other responsibilities, albeit unofficially. Upon the discretion of the President, the Vice President may be involved in framing domestic and foreign policies.