According to
www.politics1.com for Monday, September 18, 2006. The freshman Senator from Illinois was stumping in Iowa for Iowa Senator Tom Harkin (D). He said he was focusing on 2006, but did not explicitly rule out throwing his hat into the 2008 ring.
Being a freshman Senator from Illinois, a heavily Democratic state because of Chicago, and a popular Senator from Illinois, would he have a better chance in 2008 or 2012?
I personally think 2012 would be his better shot, but with the field wide open in both parties, anything can happen.