Presidential hopeful Sen. Barack Obama, D-Ill., speaks to supporters before kicking off a canvas at East High School in Des Moines, Iowa, Saturday, Oct. 13, 2007. (AP Photo/Kevin Sanders)
Presidential hopeful Sen. Barack Obama, D-Ill., walks to a house during a neighborhood canvas in Des Moines, Iowa, Saturday, Oct. 13, 2007. (AP Photo/Kevin Sanders)
Presidential hopeful Sen. Barack Obama, D-Ill., walks down a sidewalk with members of the media in tow during a neighborhood canvas in Des Moines, Iowa, Saturday, Oct. 13, 2007. (AP Photo/Kevin Sanders)
Presidential hopeful Sen. Barack Obama, D-Ill., walks down to the sidewalk from a house during a neighborhood canvas in Des Moines, Iowa, Saturday, Oct. 13, 2007. (AP Photo/Kevin Sanders)
Presidential hopeful Sen. Barack Obama, D-Ill., waits patiently for someone to answer the door during a neighborhood canvas in Des Moines, Iowa, Saturday, Oct. 13, 2007. (AP Photo/Kevin Sanders)
Presidential hopeful Sen. Barack Obama, D-Ill., speaks with supporters on the front steps of their house during a neighborhood canvas in Des Moines, Iowa, on Saturday, Oct. 13, 2007. (AP Photo/Kevin Sanders)