"We want the voters to have their say. That's over on June 3," he said in an interview on ABC's "Good Morning America."
Dean, saying he was speaking from experience as a candidate for president in 2004, said he won't have to force anyone from the race.
"Either of these candidates, if it's time for them to go, they'll know it and they will go," he said. "They don't need any pushing from me. You know when to get in and you know when to get out. That's just part of the deal."
"This is not about Hillary Clinton and Barack Obama," Dean added. "This is about our country. It's about a better course for our country. ... We've got to move on and win the presidency."
Obama has more delegates and popular votes than Clinton, but she also is fresh off a big-state win in Pennsylvania.
Indiana and North Carolina hold primaries on May 6.
Dean also said that while party rules say superdelegates can wait until the August convention to make up their minds, that would be too late to unify the party and defeat the presumptive Republican nominee, John McCain.
"We really can't have a divided convention. If we do it's going to be very hard to heal the party afterwards," Dean said. "So we'll know who the nominee is and that'll give us an extra 2 1/2 months to get our party together, heal the wounds of having a very closely divided race and take on Senator McCain."
