The challenges facing Sen. Barack Obama as he tries to woo supporters of former rival Sen. Hillary Rodham Clinton could pale in comparison with Sen. John McCain's troubles with female voters - if the voices of a growing number of prominent Republican women are any indication.

"I cannot see a more counterproductive candidate for women," said Jillian Manus-Salzman, a leading California Republican activist and generous GOP donor in the nation's most populous state, an ATM for presidential campaigns. "I cannot vote for McCain."

Susan Eisenhower - granddaughter of former GOP President Dwight Eisenhower and a Washington, D.C.-based expert on foreign policy and national security issues - said Wednesday she is backing Obama over McCain because the Democrat has shown more understanding of how the Iraq war, the economy and other key issues affect women's daily lives.

And Harriet Stinson, the 82-year-old founder of Bay Area-based Republicans for Choice, said that - after 60 years of Republican registration - she has finally reregistered as a Democrat.

"I couldn't take it anymore," she said, arguing that on issues like funding birth control and support of sex education, McCain "couldn't be worse."

Competing voices

The comments come as Michelle Obama gets high-profile face time on television's "The View" this week, talking up family matters, and former Hewlett-Packard Chief Executive Officer Carly Fiorina, acting in recent days as surrogate-in-chief for GOP candidate McCain, is promoting his support among female voters.

Much attention has focused in recent weeks on the discontent of leading Democratic women who supported Clinton, including Susie Tompkins Buell - one of the Democratic Party's most generous and influential donors. The San Francisco-based entrepreneur has warned that many of Clinton's female supporters are absolutely not ready to support Obama, the party's presumed presidential nominee.

Buell has led a vocal group of women behind a political action committee called WomenCount (www.womencountpac.com), which plans a new campaign of full-page newspaper ads to address what she calls lingering concern regarding the party's disengagement with older women during and after Clinton's historic race as the first major female candidate for president.

Such efforts underscore how women are considered the must-have vote in the contest between McCain and Obama, said Barbara O'Connor, professor of political communication at Cal State Sacramento, "especially in a close election, because there are more of them, and they vote more regularly."

O'Connor said the disappointment of Clinton Democratic women is understandable - but unlikely to last for long.

Baby Boomer women "wanted to vote for a woman as president before they died," she said. But "when they calm down, they'll take a look at McCain's position on choice, on drilling the California coast ... and I can't believe these Democratic women activists will entrust their future to John McCain.

"While McCain is refreshing compared to his peers, and a solid citizen on his values ... he's really a Republican in his heart on social issues. And that's going to drive the average soccer mom around the bend," O'Connor said.

Ellen Malcolm, who heads the Democratic pro-choice Emily's List, the nation's largest political action committee, said her group is one of many that will educate women to McCain's positions on issues like judicial appointments and offshore oil drilling.

'Common ground'

"Hillary supporters will find tremendous common ground with Barack Obama," said Malcolm, a Clinton backer. "He believes what they believe. John McCain believes what George Bush believes."

Stinson said GOP women must ask critical questions of their candidate.

"If McCain is so against abortion," she asks, "why does he oppose all the measures needed to reduce the need for it - making insurance companies cover contraceptives, federal funding for birth control and comprehensive sex education?"

Some major Democratic Party donors, like philanthropist Eleni Tsakopoulos-Kounalakis - president of Sacramento-based AKT Development Corp. who has written checks to Clinton since her first Senate race in 2000 - say that even for some Democrats, the idea of getting behind Obama was "hard, no question about it."

But she has come around, she says, and she believes many women, Republican and Democratic alike, will follow suit.

"After many days of feeling very sad," the Democratic insider said she went online this week and did what was once unthinkable - "maxed out," writing the maximum donation to Obama's presidential campaign.

Fiorina, in recent events, has tried to stress McCain's sympathy and connection with Clinton and her female supporters.

"Having started as a secretary and eventually becoming a CEO, I not only have great admiration and respect for Hillary Clinton, and her candidacy and leadership, but I also have great empathy, I must tell you, for what she went through," Fiorina said. "I also believe, though, if we are striving for a gender-blind, color-blind society, that we really ought to be focused on the person that we think will make the right judgments ... that person is John McCain."

Move toward Obama

Manus-Salzman said she hasn't yet endorsed Obama, but she will not be surprised if Republican women begin writing checks and openly expressing their support.

"I would have had a hard time selling Republican women on Hillary Clinton," she said. "But selling Republican women on Barack Obama is a whole different story."

"They don't see him as a partisan," she said. "My instinct, as a woman, is that this is a truly special person who respects women, who will listen to our voice and use women to rejuvenate and resurrect this country."

John McCain on abortion -- "I'd love to see a point where (Roe vs. Wade) is irrelevant, and could be repealed because abortion is no longer necessary. But certainly in the short term, or even the long term, I would not support repeal Roe vs. Wade, which would then force X number of women in America to (undergo) illegal and dangerous operations." McCain said he would support legislation banning abortions in the third trimester. - Interview with The Chronicle, Aug. 20, 1999 -- "After a lot of study, a lot of consultation and a lot of prayer, I came up with a position that I believe there should be an exception for rape, incest or the life of a mother ... (the issue) is one of the most difficult and agonizing issues that I think all of us face, because of our belief - yours and mine - that life begins at conception." - Reported in the New York Times, Jan. 22, 2000 -- "John McCain believes Roe v. Wade is a flawed decision that must be overturned, and as president he will nominate judges who understand that courts should not be in the business of legislating from the bench." - McCain for President Web site