Democratic presidential candidate, Sen. Barack Obama, D-Ill, holds his BlackBerry before holding a conference call with supporters gathering at an event in Charlotte, N.C. , in St. Louis, Mo. , Monday, July 7, 2008, after Obama's campaign plane made an unscheduled stop in St. Louis to deal with a mechanical, flight control problem and prevented his appearance at the event. AP Photo logo AP Photo 19 months ago

Democratic presidential candidate, Sen. Barack Obama, D-Ill, holds his BlackBerry before holding a conference call with supporters gathering at an event in Charlotte, N.C. , in St. Louis, Mo. , Monday, July 7, 2008, after Obama's campaign plane made an unscheduled stop in St. Louis to deal with a mechanical, flight control problem and prevented his appearance at the event.