Recent public opinion polls show a growing number of Democrats want presidential candidate Barack Obama to choose rival Hillary Clinton as his vice presidential running mate, if he wins the Democratic Party's presidential nomination.   But as VOA National correspondent Jim Malone reports, a lot of political experts think an Obama-Clinton ticket is unlikely.

To some Democrats, Obama and Clinton together would the be the dream ticket.  Others see them as the political equivalent of the odd couple.

For example, there was that New Hampshire debate where Clinton was asked why Obama was more likeable. She responded, "Well, that hurts my feelings, but I will try to go on.  He is very likeable.  I agree with that.  I do not think I am that bad." 

Obama responded to Clinton’s message by saying, "You are likeable enough, Hillary.  No doubt about that."

It has been a long and bitter campaign, and the idea of two rivals joining forces might seem far-fetched.  But some experts say a joint ticket could unify the party in time for the general election campaign against the presumptive Republican nominee, Senator John McCain.

John Fortier of the American Enterprise Institute, says, "And if he really believes that he needs a national figure with some experience who can appeal to white working class voters, then he may overcome the bitterness that they have, the worries that he has about Senator Clinton in other ways."

Obama has drawn support from younger voters and African-Americans.  He could benefit from Clinton's appeal to women, seniors and white working class voters.

But there are also plenty of reasons why a joint ticket might not work. Relations between the candidates are tense after a long and bitter campaign. In addition, Hillary Clinton tends to be a polarzing figure. 

Stephen Hess of the Brookings Institution says, "The problem with Mrs. Clinton is that there are a lot of people who do not like her very much, and those are people who probably would not vote against Obama because she is on the ticket, but possibly they would not work as hard.  They would not show the same enthusiasm for the ticket, or they might even stay home."

Also, Obama picking Clinton as his running mate could undermine his main theme of change.

John Fortier adds, "He is first and foremost going to want to say: I am a change candidate, I am a new person.  I won this race.  I have got my own person, I do not have to pick Hillary Clinton."

Political rivals have joined forces in the past to win elections.

Democratic senators John Kennedy and Lyndon Johnson ran as a ticket in 1960.  Twenty years later, Republicans Ronald Reagan and George Bush did the same.

Kennedy's decision to pick Johnson was crucial, Hess said. "The Lyndon Johnson-John Kennedy team was probably the only case in American history where choosing a vice presidential nominee very likely won the election for the candidate,"  he explained.

Assuming he wins the nomination, Obama is expected to choose a running mate sometime before the Democratic National Convention in late August.