>> barack obama makes the most important speech of his campaign. >> it took place in philadelphia. the subject was race. >> we cannot solve the challenges of our time. unless we solve them together. >> that was a high wire moment. in speaking to michelle afterward she said that was the proudest she had been the entire campaign. >> the speech put the campaign back on track. and helped obama clench the democratic nomination for president. but the victory was over shadowed by a simple gesture. a fist bump. that pushed criticism to a new level. when it happened most people throughout the country could relate. and then on fox news. >> a fist bump. a pound? a terrorist fist jab? >> and it becomes a scandal. during the campaign. >> they began to paint the obama's as radical figures.