THE Single Anxious Female has taken over from the soccer mom of the 1990s and the stockcar-racing Nascar dad of the Bush era as the influential new voting block that could deliver victory to Hillary Clinton in the 2008 presidential election.

Many of the 18 to 44-year-old single women who watched Sex and the City, the television series, now want a woman in the White House. They are concerned about terrorism, angry about the Iraq war and worried about affordable health-care and education, according to the Clinton camp.

“I think the better way to define them is SAFs,” said Ann Lewis, a senior adviser to Clinton. “Single Anxious Females.”

Samantha Waterman, 41, a Clinton supporter and SAF from Los Angeles, believes the glamorous girlfriends in Sex and the City would be for Hillary.

“I think they might be Hillary women. They’re waiting to start their lives because they haven’t met Mr Right yet or had a baby. What they are searching for is security. They would admire Hillary because she is so strong and steady.”

Most Single Anxious Females cannot afford the high-heeled Manolo Blahnik shoes that Carrie Bradshaw, the narrator of the TV series, loves to wear: they tend to be relatively poorly educated, move home frequently and earn less than $30,000 (£15,000) a year, according to New York magazine.

But they are an increasingly visible and politically active group, which Clinton has high hopes of attracting. Single women represented 22.4% of the US electorate at the last election, up from 19% in 2000, and the figure is set to rise again in 2008.

Maren Hesla, a director of Emily’s List, the campaigning group for women in politics, said single women’s “voting muscle” was growing rapidly in strength. “It’s a group we’ve been tracking with a lot of interest because they’re close to becoming the Democratic party base. They regard Hillary Clinton as a role model who can break through the glass ceiling for all of us.”

Barack Obama, the handsome Democratic senator for Illinois, is causing a flutter among the same group. Jennifer Aniston, the archetypal Hollywood Single White Female, turned up at a celebrity fundraiser for him in Los Angeles earlier this year. But Clinton is to hit back this Wednesday with a gathering to be attended by the film star Penelope Cruz, the “shagadelic” Heather Graham, of Austin Powers fame, and Eva Longoria from Desperate Housewives.

The polls show that Clinton is winning the battle for the female vote, so far. According to a report in last week’s Washington Post, 38% of women in their forties are backing Clinton in the Democratic primaries, compared to just 17% of men. Among 18 to 39-year-old women, the former first lady outpolls Obama by 45% to 22%.

Katie Roiphe, 37, a writer and cultural critic, said: “It’s possible Hillary appeals to Single Anxious Females because she is the most independent married woman there is.

“She’s not a housewife or Laura Bush figure and she might as well be single in certain respects. Even when her husband was cheating on her more publicly than anybody had been cheated on before, she remained nonchalant. She had made her peace with who he was.”

In 2004, only 59% of unmarried women voted, compared to 71% of married women. Clinton believes she can tap the missing 6m unmarried women who did not bother to vote. She has been attending women-only events in key primary states and her “listening” campaign is designed to offer women a voice.

Naomi Wolf, 44, the feminist writer and author of The End of America, said politicians had long been aware that single women could swing the election. Wolf tried to increase their turn-out when she was an adviser to Al Gore in 2000, but politics tended to be run then by “old white guys”.

“It sounds like this group of women is getting more and more engaged. Hillary’s machine is top-notch,” said Wolf. But they will not automatically flock to Clinton, she cautioned. “I really admire her, but unfortunately her demeanour is very upscale. There is a class difference she needs to bridge.”

Wolf compares Clinton to the aloof boss played by Sigourney Weaver in the film Working Girl, while the single female voters she needs to attract are more like bubbly, down-to-earth Melanie Griffith, her secretary. “It’s going to be a challenge for Hillary. They’re not going to be swept along on the basis that ‘she’s one of us’, because they don’t really see her that way. They see her as somebody they can work for.”

Top Republican advisers Mary Matalin and Karen Hughes ran rings around the Democrats for the women’s vote in 2004, Wolf believes. “Horribly enough, the Bush administration was good at reaching women. They’d say, ‘Why did we go into Afghani-stan? Because girls were kept out of school.’ They had a way of making every policy sound like Take Your Daughter to Work Day.”

Despite his roguish past, Bill Clinton is helping to bring Single Anxious Females into his wife’s camp. “I like Bill,” said Waterman. “Honestly, I think more men than women got upset with him for fooling around. Maybe it’s a guilt complex. Women are better able to forgive him.”

Roiphe also believes the former president is an asset. “A lot of women support Hillary but they can’t get excited about her. It’s a big problem for her that women will always love Bill more than her.”

Key voters

Soccer Mom Moderate, suburban swing voter. Backed Bill Clinton in 1990s but morphed into “security mom” after 9/11

Nascar Dad Bush-voting, middle-American stock car-racing sports fan. Backed the Iraq war in 2004

Single Anxious Female Ms Worried about war in Iraq, health and education. Ready for a woman president

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