Each House, in judging of elections under this clause acts as a judicial tribunal, with like power to compel attendance of witnesses. In the exercise of its discretion, it may issue a warrant for the arrest of a witness to procure his testimony, without previous subpoena, if there is good reason to believe that otherwise such witness would not be forthcoming.[159] It may punish perjury committed in testifying before a notary public upon a contested election.[160] The power to judge elections extends to an investigation of expenditures made to influence nominations at a primary election.[161] Refusal to permit a person presenting credentials in due form to take the oath of office does not oust the jurisdiction of the Senate to inquire into the legality of the election.[162] Nor does such refusal unlawfully deprive the State which elected such person of its equal suffrage in the Senate.[163] "A QUORUM TO DO BUSINESS" For many years the view prevailed in the House of Representatives that it was necessary for a majority of the members to vote on any proposition submitted to the House in order to satisfy the constitutional requirement for a quorum. It was a common practice for the opposition to break a quorum by refusing to vote. This was changed in 1890, by a ruling made by Speaker Reed, and later embodied in Rule XV of the House, that members present in the chamber but not voting would be counted in determining the presence of a quorum.[164] The Supreme Court upheld this rule in United States _v._ Ballin,[165] saying that the capacity of the House to transact business is "created by the mere presence of a majority," and that since the Constitution does not prescribe any method for determining the presence of such majority "it is therefore within the competency of the House to prescribe any method which shall be reasonably certain to ascertain the fact."[166] The rules of the Senate provide for the ascertainment of a quorum only by a roll call,[167] but in a few cases it has held that if a quorum is present, a proposition can be determined by the vote of a lesser number of members.[168] RULES OF PROCEDURE