John Marshall Butler

U.S. Sen. Barbara Mikulski will turn 72 years old on July 20. If -- more like when, as her aides will point out -- she seeks re-election in 2010, she will be 80 years old at the end of that term.

Sen. Millard E. TydingsDuring his tenure, President George W. Bush has never endorsed a primary challenge to an incumbent member of Congress - no matter how much they disagreed with his policies.

And Bush is not alone in history. No sitting president has backed the ousting of party members (at least via popular elections) in 70 long years, since Franklin Delano Roosevelt took on Senator Millard E. Tydings and several other Democrats from across the country.