In nominating Senator Joe Biden for vice president this week, Democrats predictably select a senator to fill the office that presides over the Senate. Since 1944, Democratic National Conventions have nominated senators for vice president in sixteen of seventeen elections. Geraldine Ferraro stands as the only vice presidential nominee since 1944 who never served in the Senate. (Sargent Shriver never served in the Senate, but since he replaced Senator Thomas Eagleton on the ticket several weeks after the convention had adjourned he is excused from this discussion.) What explains this peculiarity? Democrats, the party that looks to Washington for solutions, looks to the Senate for vice presidential candidates. Republicans, who in theory at least maintain an outlook decidedly more federalist, have been more diverse in the choices for the lower half of the presidential ticket. I hope they think outside of the rotunda, as in the capitol rotunda, once again. The Senate seems an incestuous club less concerned with furthering ideas than maintaining collegial relations, which is one of the reasons the bizarre talk of Senator Joe Lieberman, the Democratic nominee for vice president in 2000, as John McCain's running mate so sickens me. It's also interesting that sitting U.S. senators have won the presidency in just two elections (Warren Harding and John Kennedy) during the past century. A contest between John McCain and Barack Obama is certain, unfortunately, to buck that trend.