Democrat Barack Obama has ridiculed the idea of being Hillary Rodham Clinton's running mate this fall.
Speaking in Columbus, Miss.,Monday, the Illinois senator said voters should not think they can get both candidates on the ticket by nominating Clinton as president and assuming he will accept the vice presidential spot.
Obama told a midday crowd, "You have to make a choice in this election."
Obama did not absolutely close the door to a second spot on the ticket, but it was his most pointed signal that he is not interested.
He also said he didn't know how somebody who is in second place is offering the vice presidency to the person who is in first place. That drew cheers and a long standing ovation from about 1,700 people.
Obama noted that he has won more states, votes and delegates than Clinton so far, and he says he thinks he can win the nomination.