Obama defeated several candidates in the Democratic primary: Hillary Clinton, senator from New York and wife of former president Bill Clinton; John Edwards, former U.S. senator from North Carolina; Joe Biden, U.S. senator from Delaware; Chris Dodd, U.S. senator from Connecticut; Mike Gravel, former U.S. senator from Alaska; Dennis Kucinich, U.S. representative from Ohio; and Bill Richardson, governor of New Mexico.

It turned out to be a contest between Obama and Clinton. He defeated her by garnering more than 2,300 delegates—more than the necessary 2,117. Clinton ran a tough race and obtained nearly 2,000 delegates herself.