Democrats who worry that Barack Obama is untested can put their concerns to rest. The inflammatory rhetoric of the Rev. Jeremiah Wright has confronted Obama with the most severe test of his presidential campaign and, quite likely, of his public career. He is now facing a full-blown and fast-moving political crisis in which his reputation as a leader with a singular ability to transcend racial divisions and unite Americans is in jeopardy. A convergence of factors - a media firestorm, a Democratic rival eager to exploit his stumbles and, most of all, a Republican opposition eager to rough up the man they expect to face in the general election - have raised the stakes to new heights for Obama with the speech he will deliver in Philadelphia on Tuesday morning. A successful address would go a long way toward answering Hillary Rodham Clinton’s complaint that Obama has never shown he can handle the rough-and-tumble nature of modern political combat. A failure could leave many of the white independent voters - a key group behind Obama’s swift rise in national politics - doubting whether he is really the bridge-builder and healer he has portrayed himself to […]