What happens if there is a tie in the senate and there is no vice president?
Under the Senate's rules, a bill has to receive a majority (meaning more than half) of the votes to pass. Therefore, if there is a tie and there is no Vice President to break the tie, the bill fails because is has not received a majority.
A previous answer asserted that the President Pro Tempore would break the tie--however, the President Pro Tem is a Senator and therefore would presumably have already voted.
The Vice President of the United States is the designated President of the Senate as is set forth in the US Constitution. However when the Vice President is away then the Senate's president pro tempore (or any others so designated) is the acting President of the Senate. For any vote in the Senate that ends in a tie, only the Vice President can cast the tie-breaking vote.
There is no such office as vice president of the Senate. The Vice President of the United States presides over the Senate and is thus often referred to as the President of the Senate. In that capacity, the Vice President presides over the Senate when it is in session. In that capacity, the Vice President's most notable role is to cast the deciding vote in the event of a tie vote on the floor of…