in order for senate or house to vote on a bill how many members must be present
Quorum Article I, Section 5, Clause 1 of the United States Constitution provides that "Each House shall be the Judge of the Elections, Returns and Qualifications of its own Members, and a Majority of each shall constitute a Quorum to do Business..." Therefore, in both the House of Representatives and the Senate a quorum is a simple majority of their respective members. The only exception is that stated in the Twelfth Amendment, which provides that in cases in which no candidate for President of the United States receives a majority in the Electoral College, the election is decided by the House of Representatives, in which case "a quorum for this purpose shall consist of a member or members from two-thirds of the states," and in cases in which no candidate for Vice President of the United States has been elected, the election is decided by the Senate, in which case "a quorum for the purpose shall consist of two-thirds of the whole number of Senators."