Although the qualifications of electors of Members of Congress are defined by State law,[116] the right to vote for such Representatives is derived from the Federal Constitution.[117] Unlike the rights guaranteed by the Fourteenth and Fifteenth Amendments, this privilege is secured against the actions of individuals as well as of the States.[118] It embraces the right to cast a ballot and to have it counted honestly.[119] Where a primary election is made by law an integral part of the procedure of choice or where the choice of a representative is in fact controlled by the primary, the Constitution safeguards the rights of qualified electors to participate therein.[120] Congress may protect this right by appropriate legislation.[121] In prosecutions instituted under section 19 of the Criminal Code,[122] the Court had held that failure to count ballots lawfully cast,[123] or dilution of their value by stuffing the ballot box with fraudulent ballots[124] constitutes a denial of the constitutional right to elect Representatives in Congress. But the bribery of voters, although within reach of Congressional power under other clauses of the Constitution, is not deemed to be an interference with the rights guaranteed by this section to other qualified voters.[125] WHEN THE ABOVE QUALIFICATIONS MUST BE POSSESSED The principal disputes which have arisen under these sections have related to the time as of which members-elect must fulfill the conditions of eligibility, and whether additional requirements may be imposed by federal or State law. Although on two occasions when it refused to seat persons who were ineligible when they sought to take the oath of office, the Senate indicated that eligibility must exist at the time of election, it is now established in both Houses that it is sufficient if the requirements are met when the oath is administered. Thus persons elected to either House before attaining the required age or term of citizenship have been admitted as soon as they became qualified.[126] ENLARGEMENT OF QUALIFICATIONS