Sen. Joe Lieberman, Connecticut Democrat-turned-independent, addressed the Republican National Convention in St. Paul, Minn., on Sept. 2, 2008, a little more than a week after maverick former Rep. Jim Leach, Iowa Republican, spoke at the Democratic National Convention in Denver, on Aug. 25 of that year. (Associated Press)

Sen. Joe Lieberman, Connecticut Democrat-turned-independent, addressed the Republican National Convention in St. Paul, Minn., on Sept. 2, 2008, a little more than a week after maverick former Rep. Jim Leach, Iowa Republican, spoke at the Democratic National Convention in Denver, on Aug. 25 of that year. (Associated Press)