U.S. Presidential Campaign Trails (in chronology): Candidates-20

(L-R) Presidential hopeful Sen. Hillary Clinton (D-NY) speaks to a crowd gathered in Simpson College in Indianola, Iowa, on Saturday, Nov. 3, 2007; and U.S. Presidential hopeful Sen. Barack Obama (D-IL) speaks at the Grundy Center High School in Grundy Center, Iowa, on Nov. 18, 2007.

(L-R) Presidential hopeful Sen. Hillary Clinton (D-NY) speaks to a crowd gathered in Simpson College in Indianola, Iowa, on Saturday, Nov. 3, 2007; and U.S. Presidential hopeful Sen. Barack Obama (D-IL) speaks at the Grundy Center High School in Grundy Center, Iowa, on Nov. 18, 2007.