Proving Grounds

Presidential hopefuls devote more time and money to Iowa than any other state because past caucuses have catapulted long shots and crushed front-runners.

Former presidential candidates discuss how the New Hampshire primary has produced some of the most dramatic moments in campaign history, and how the state has influenced the U.S. political landscape for decades.

The South Carolina presidential primary, who won the election, and who fell victim to the questionable campaign tactics.