Some supporters of Hillary Clinton are voicing anger that Barack Obama may choose another woman for his vice presidential running mate.
Rumors that other high profile women politicians -- such as two-term Kansas Gov. Kathleen Sebelius and first-term Missouri Sen. Claire McCaskill -- are fueling a backlash of sorts from some of Clinton's most ardent supporters.
"Hillary Clinton in not a political lego block, easily replaced by another woman candidate," Allida Black, a former Clinton national fundraising committee member, told ABCNews.com Thursday.
"Governor Sebelius, while a good leader for Kansas, is not, in any way, an acceptable substitute for Senator Clinton," said Black, who is also director of the Eleanor Roosevelt Papers Project at George Washington University.
"Women voters know this," Black said. "Hillary is not interchangeable."
"Here she is a candidate that received more votes than anyone in primary history and why would he discard her for another woman vice president; that would be insulting," said Democrat Will Bower, co-founder of PUMA, which stands for Party Unity My A**, a Washington, D.C.- based group urging Clinton to fight for the nomination all the way to the party's Denver convention in August.
"I really don't care who he chooses as vice president because I'm not going to vote for him regardless," said Bower, who said he'll vote for Republican Sen. John McCain if Clinton isn't at the top of the ticket.
Lanny Davis, former special counsel to President Bill Clinton and a longtime friend of the Clintons dating back to their time together at Yale Law School, also blasted the idea of another woman running as Obama's vice presidential pick.
"The selection of either one of those instead of Senator Clinton I would find completely incomprehensible," Davis told ABC News.com.
Davis argued that while he respects Sebelius and McCaskill, Clinton supporters would have a hard time accepting another woman on the ticket.
"If anyone thinks that picking a woman will simply placate Hillary Clinton's female supporters, I think that's very patronizing to women and I don't think that that either Governor Sebelius or Senator McCaskill would disagree," he said.
Davis, who wrote an op-ed in the Wall Street Journal on Thursday titled "Why Obama Should Pick Hillary," said he hasn't given up the "dream" of an Obama-Clinton ticket.
"She helps him more and she's more qualified," he said, "why would he pick two females, both who are very admirable public servants, why would you pick them over her?"
Other Clinton supporters seem less confident that an Obama-Clinton "dream ticket" lives on.
Two former Clinton campaign staffers who started the Website VoteBoth.com to urge Obama to choose Clinton as his running mate is shutting down under the assumption that she's not on his short-list of vice-presidential candidates.
"Because Senator Obama is no longer considering putting Senator Clinton on the ticket, we do not think continuing to lobby for it helps him win," VoteBoth.com founder and former Clinton campaign press aide Sam Arora said.
The former Clinton staffers, who have worked for Clinton for a combined 10 years, thanked "tens of thousands" of supporters who they said petitioned, called and wrote letters to Obama, urging him to pick Clinton as his running mate.
"Because of your work, Senator Obama asked Hillary to be his keynote speaker at the Democratic National Convention," Arora and VoteBoth.com co-founder Adam Parkhomenko wrote on their Website. "Regretfully, this means that Senator Hillary Clinton is no longer under consideration as Senator Obama's running mate."
Parkhomenko is a former executive assistant to Patti Solis Doyle, Clinton's former campaign manager who was fired in February and now works for the Obama campaign, awaiting the presumptive Democratic nominee's vice-presidential pick, whom she will serve as chief of staff.
Arora, a former Clinton campaign press aide, is now attending law school.
Officially, the Democratic convention speaker schedule has not been publicly released. And the Obama campaign is keeping the details of whom they are considering as a potential vice presidential candidate a closely guarded secret.
"The schedule for the convention has not been finalized," Obama spokesperson Bill Burton told ABCNews.com. "We're not commenting about the nominee selection process."
But Nedra Pickler of The Associated Press has reported that Obama and Clinton advisers have said Clinton is likely to speak on the second night of the party's August convention in Denver -- coinciding with the anniversary of the ratification of the amendment giving women the right to vote.
Obama spent several hours this week meeting with the co-chairs of his vice presidential committee search team Eric Holder and Caroline Kennedy in Washington.
Potential Democratic vice-presidential contenders include Virginia Gov. Tim Kaine, Indiana Sen. Even Bayh, Delaware Sen. Joe Biden, New Mexico Gov. Bill Richardson and Sebelius, a two-term governor of a traditionally red state, and McCaskill, a first-time senator from a battleground state who is close to Obama.
McCaskill campaigned with Obama in Missouri on Wednesday, but she has said she's not being vetted, and sources close to her describe her role as a close personal advisor rather than a possible veep candidate.
This week Sebelius sidestepped speculation about being on Obama's vice-presidential short-list.
"All the information on the vice-presidential process is really being answered by the campaign," Sebelius told a Kansas ABC affiliate on Tuesday.
While Washington reporters are busily chasing rumors about who's on Obama's veep short-list, voters may be less interested.
McCain and Obama's choice of running mates ranked dead last in importance among voters polled recently by ABC News, with only 15 percent of likely voters calling the candidates' veep choice "extremely important."
Of far greater concern to voters is the economy, gas prices and the Iraq war, according to the latest Washington Post/ABC News poll.
Even among Clinton's primary supporters, only 24 percent said the choice of a running mate would be extremely important in their vote in November.
And Clinton's name on the ticket wouldn't necessarily boost Obama's support.
If Clinton were on the ticket with Obama, 23 percent said that would make them more likely to vote for the Democratic ticket, but an essentially identical 22 percent said it would make them more likely to vote for the Republican ticket, according to the July Washington Post/ ABC News Poll.
Since losing the bitterly fought Democratic primary battle to Obama, questions remain about how engaged Clinton will be in Obama's general election campaign.
In the past, Obama has said Clinton "would be on anybody's short-list," but there has been little activity between the two former rivals since they appeared together at a campaign rally last month in Unity, N.H., and at subsequent fundraisers.
And Clinton hasn't been a high-profile surrogate for Obama.
The former first lady has appeared preoccupied not with electing Obama but with retiring her own $25 million in campaign debt, sending out an e-mail to supporters this week asking for a $5 donation to her campaign for a chance to dine with her "under the stars."
Clinton, who lost her bid to be the Democratic Party's first woman presidential candidate, won 52 percent of Democratic women voters during the primaries. Obama leads McCain 54 to 39 percent in support from likely women voters, according to the latest ABC News/Washington Post poll.
While some ardent Clinton supporters said they would be angry if another woman were chosen as Obama's vice-presidential candidate, others said they would support whomever Obama chooses -- even another woman.
"If that's going to help him secure the White House, then we need to support him," said Dana Kennedy, 40, a former Clinton supporter who went state-to-state campaigning for Clinton during the primary. "The stakes are way too high not to rally behind the nominee."
ABC News' Gary Langer, Peyton Craighill, Tahman Bradley, Kate McCarthy and Matt Jaffe contributed to this report.