WASHINGTON -- President Barack Obama is calling for national unity ahead of Sunday's anniversary of the Sept. 11 attacks and reflecting on a decade that tested America's character."The terrorists who attacked us that September morning are no match for the character of our people, the resilience of our nation or the endurance of our values," the president said Saturday in his weekly radio and Internet address a day ahead of the 10th anniversary of the attacks.Read More... More on September 11 Anniversary