NEW YORK: Hillary Clinton has the biggest chance in United States (US) history of shattering the ultimate glass ceiling and becoming the first female commander-in-chief. But could men spoil it for her?

On paper, few White House candidates have been more qualified: a two-time senator, a two-term first lady and a former secretary of state who was on the job when America killed most wanted man Osama bin Laden.

All but guaranteed the Democratic nomination, she is nonetheless losing more white male voters to her leftist challenger Bernie Sanders than she did to Barack Obama in 2008.

"I mean nobody's perfect but I don't trust her, she's too slick. I'd rather have her husband," said George Ruzzier, 81, a former independent and Democrat at a Donald Trump rally, who said he was voting Republican this year.

He's not alone. Sixty-eight per cent of white men have an unfavourable opinion of Clinton, according to a recent Quinnipiac University poll.

Clinton's vulnerabilities were on display as she lost seven out of the last eight primary elections and caucuses to Sanders, who cornered the male Democrat vote 64 to 35pc in Wisconsin, according to CNN exit polls.

Male voters gripe about Clinton's ability to revive the economy. They complain she is opportunistic, not honest and does not care about them as she champions minority rights and gun control.

Other opposition has been attributed to latent sexism, white liberal disappointment in Obama and Sanders's economic populism.

Challenge

But strategists say it presents a serious, if not fatal weakness for Clinton going forward into a November election against any of the remaining Republican candidates ─ even Trump, who polls poorly amongst women.

"This is a challenge for her," says Jeanne Zaino, professor of political science at Iona College in New York. "She hasn't been able to appeal the way Bernie Sanders has to that constituency."

"If you look back eight years, she was winning white male voters and then-candidate Obama was struggling. She's gone full circle."

In a primary season that could elect the first female presidential nominee, Trump has made attitudes towards women a pivotal part of the campaign, suggesting that women who have abortions should be punished and using derogatory terms to insult women he doesn't like.

Male commentators have called out Clinton for shouting and not smiling ─ to the outrage of feminists and her supporters.

While Clinton would beat Trump 46 to 40pc according to a Quinnipiac poll, she would lose the white male vote 51-34pc to the billionaire while Sanders would beat Trump overall and come neck-and-neck on the male vote.

Ardent Clinton supporter Robert Lomangino, 23, from Long Island believes "100pc" that she suffers in public perception for being a woman.

"She gets a much rougher go at it," he told AFP after a Clinton rally in Harlem, New York.

"Bernie Sanders can go up on stage and shout as loud as he wants and point his finger and look almost mean and taunting, and Hillary Clinton can never do that. If she even raises her voice, she gets criticised for being shrill, and it's a little unfair."

To some, America's ongoing quest for its first female leader is strange in a country that arguably offers no better home to the pioneering woman.

Policy problem

Pakistan, for example, has one of the most abysmal records on women's rights anywhere in the world and yet, Benazir Bhutto was elected prime minister for the first time nearly 30 years ago.

In contrast, Americans made up more than half Forbes's 100 most powerful women list in 2015, including seven of the top 10.

Pop starlet Taylor Swift, 26, was the youngest and Americans led 12 of the 18 categories as diverse as finance, technology, media and manufacturing.

Zaino says Clinton's disconnect with white men is primarily policy-oriented rather than sexism, given that she is still the leading candidate.

Sanders has been stronger on issues of free trade and campaign finance reform, which resonate well with men, Zaino told AFP.

"She is going to have to try very, very hard to capture that energy and that support of Sanders's voters," she said.

Clinton supporter Sam Ackerberg, a 27-year-old law student originally from Minneapolis and now living in New York, says men should be the ones to adjust.

"We all have mothers, sisters, friends, aunts, and women's issues should matter to us," he said.