US Democratic presidential candidate Sen Barack Obama speaks at the 38th constitutional convention of the Pennsylvania AFL-CIO in Philadelphia

 
US Democratic presidential candidate Sen Barack Obama speaks at the 38th constitutional convention of the Pennsylvania AFL-CIO in Philadelphia
US Democratic presidential candidate Sen. Barack Obama (D-IL) speaks during an appearance at the 38th constitutional convention of the Pennsylvania AFL-CIO in Philadelphia, Pennsylvania April 2, 2008. REUTERS/Tim Shaffer (UNITED STATES) US PRESIDENTIAL ELECTION CAMPAIGN 2008 (USA)