Centrist Democratic Senator Jim Webb, a key Obama ally from the 'purple' state of Virginia, will retire from the Senate in 2012. Readers will remember Senator Webb as the gentleman who won a close race against Republican George "Macaca" Allen in 2006.
It is believed that former Virginia Governor Tim Kaine leads the pack of potential Democrats for the newly opened seat. Obama won Virginia in 2008 before the state elected Republican Bob McDonnell as governor in 2009.
As for Webb's future, I would think that he'd make a great replacement for Robert Gates as Secretary of Defense.