NEW YORK - SEPTEMBER 11:  Presidential candidates Sen. Barack Obama and John McCain greet emergency responders Ground Zero on the 7th anniversary of the 9/11 terrorist attacks September 11, 2008 in New York City. Obama and Republican U.S presidential nominee Sen. John McCain (R-AZ) visited the World Trade Center area together to pay tribute to the more than 2,700 people killed on September 11, 2001. Getty Images logo Getty Images 14 months ago

NEW YORK - SEPTEMBER 11: Presidential candidates Sen. Barack Obama and John McCain greet emergency responders Ground Zero on the 7th anniversary of the 9/11 terrorist attacks September 11, 2008 in New York City. Obama and Republican U.S presidential nominee Sen. John McCain (R-AZ) visited the World Trade Center area together to pay tribute to the more than 2,700 people killed on September 11, 2001.