Context of S.J. Res. 7 and H.J. Res. 21 : a constitutional amendment concerning Senate vacancies : joint hearing before the Subcommittee on the Constitution of the Committee on the Judiciary, United States Senate, and House of Representatives, Committee on the Judiciary, Subcommittee on the Constitution, Civil Rights, and Civil Liberties, One Hundred Eleventh Congress, first session, March 11, 2009