WASHINGTON Now that he has sealed the U.S. Democratic presidential nomination, should Barack Obama choose vanquished rival Hillary Clinton as his vice presidential running mate?
Clinton says she is open to the idea and her supporters have begun a lobbying campaign. "I'd like to see it," said California Democratic Sen. Dianne Feinstein, a Clinton backer.
The Obama campaign was keeping its options open. "It's way too early to be talking about that," Obama senior strategist David Axelrod told reporters, while praising her as an "incredibly formidable person."
Politically, an Obama-Clinton ticket may make some sense. Clinton proved a powerful draw for white working class voters, women and Hispanics, many of whom have told pollsters they would not vote for Obama under any circumstances.
Having her on the ticket might prove a unifying force for Democrats and give Obama the edge he needs to defeat Republican John McCain in the November election. Backers of such a union see advantage in a ticket that has the potential of drawing 100 percent of Democratic support.
Democratic strategist Doug Schoen, who worked in Bill Clinton's White House, said integrating Clinton into Obama's campaign, whether as vice presidential running mate or not, must be done seamlessly or the Democrats will have trouble winning.
"She's got a substantial claim on the vice presidential nomination," said Schoen. "That's obviously Barack Obama's call, but the polling I've seen shows that if she's on the ticket, she adds swing states" that could go either way.
Clinton herself, speaking to cheering supporters in New York on Tuesday, appeared to be jockeying for the job by repeatedly bringing up the 18 million people who voted for her, about the same number as voted for Obama.
"I want the nearly 18 million Americans who voted for me to be respected, to be heard and to no longer be invisible," she said.
She said she would consult party leaders in coming days about her path forward, and that her main goal was to make sure Democrats got the 270 electoral votes needed to win the White House.
A Clinton choice could carry significant risks.
She is consistently viewed negatively by more than 40 percent of Americans, and many independent voters might be scared off by the idea of bringing her and her husband back to the White House.
A sign of the type of scrutiny the Clintons could come under emerged in a Vanity Fair magazine article this month that drew attention to some of the business deals he has used to amass a $109 million fortune less than eight years after leaving office.
"Obama would benefit from her enthusiastic involvement in his campaign," said Merle Black, a political science professor at Emory University in Atlanta.
"I don't think that would require her to be the vice presidential candidate, because that opens up a huge set of issues that would certainly affect his administration in ways that I think would be undesirable," he said.
Then there is the chemistry question. Clinton had been positioned to be crowned the nominee only to watch in horror as Obama broke ahead of her, and then she refused to give up when it was clear for weeks she was headed for defeat.
Democratic strategist Jim Duffy said he wondered, after the often bitter conflict, whether the pair would have the "mutual trust and respect needed for them to be a team."
"Maybe somehow they can figure out a way to rise above that but my sense is, based on everything I've read, is they don't particularly like each other," Duffy said.
Clinton is expected to take a little time before formally ending her campaign.
"I don't think anybody who supports Hillary has any doubt that she's going to enthusiastically support Obama and do it soon," said Democratic strategist Steve Elmendorf, a Clinton supporter.
(Additional reporting by Thomas Ferraro and Caren Bohan; Editing by Howard Goller)
(To read more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at blogs.reuters.com/trail08/)