Says in interview with NBC's "Nightly News" that after several trips to the region, believing he lacks knowledge of the differences between Sunni and Shi'ia is a "bit ludicrous." Watch clip above.
Earlier: Obama spokesman fires off sarcastic response to McCain campaign over Iraq: "We wish the McCain campaign well as they try to figure out the difference between Iran and al Qaeda...
Followed top McCain aide Salter lashing Obama's "fantasy" Iraq plan, suggests he needs to learn "national security 101."
Before that: Obama speech criticizes McCain and Clinton for voting to authorize the war. Also mocks the Arizonan for misstatement.
