Even up to January 2006 he continued to pledge to serve his full 6 year Senate term and not run for President on on the Meet the Press:
Obama: "I will serve out my full six-year term. You know, Tim, if you get asked enough, sooner or later you get weary and you start looking for new ways of saying things. But my thinking has not changed."
Russert: "So you will not run for president or vice president in 2008?"
Obama: "I will not."
Relating to a different pledge, this past month, Obama raised $150 million. That's almost double what McCain is legally restricted from raising for the entire general election campaign.
The reason for this disparity is that Obama broke his pledge to, with McCain, accept public financing for their campaigns. In his own words, Senator Obama put it this way: "I will aggressively pursue an agreement with the Republican nominee to preserve a publicly financed general election."