IF women were denied the right to vote, Mitt Romney would win the forthcoming US presidential election easily.

If only women could cast a ballot, Barack Obama would be re-elected by a landslide. The margin between the male and female vote will determine who takes possession of the White House in November, so it is no surprise that the campaign has begun with a war of manufactured outrage, aimed squarely at women.

The gender gap has been a feature of American politics since 1980, when Ronald Reagan's share of the vote was 17% higher among men. By contrast, when Bill Clinton was re-elected in 1996, his share was 17% higher among women. Last time around, Obama scraped a 1% victory over John McCain with male voters but trounced him among women by 13%.

Although Democratic efforts to exploit this divide are nothing new, they have taken a more strident tone since the Republican-controlled House Of Representatives passed the No Taxpayer Funding For Abortion Act in February 2011. The bill was a symbolic protest that predictably died in the Senate, but not before Democratic Congressman Jerry Nadler had denounced it as a "new front in the war on women and their families".

Democrats took the idea and ran with it. Congresswoman Debbie Wasserman Schultz bragged that "the war on women that the Republicans have been waging since they took over the House - is going to not only restore but possibly helps us exceed the president's margin of victory in the next election".

A series of culture war confrontations helped to sustain the theme. Republicans in Virginia proposed a bill that would require women seeking an abortion to undergo a mandatory vaginal ultrasound. In Mississippi, one of the most conservative US states, voters rejected a proposed "personhood amendment" which explicitly stated that life begins at conception. Republicans sought to cut funding for Planned Parenthood, which provides contraception and sexual health services to low-income families.

During the debate occasioned by the Republican-sponsored Blunt Amendment, which would have allowed employers to opt out of providing healthcare on moral grounds, conservative icon Rush Limbaugh picked a fight with a student named Sandra Fluke, calling her a "slut" for arguing that the health insurance plan at her university should be obliged to cover the cost of her contraceptive pill. Romney objected to Limbaugh's language, but while he was engaged in a struggle with Rick Santorum for evangelical votes, he could hardly sympathise with Fluke.

The result of all this was that, just as Romney was being confirmed as the Republican nominee, he faced a gender gap of historic proportions. In an ABC/Washington Post poll, earlier this month, he led Obama among male voters by 8% but trailed among women by 19%.

Then, during an interview on CNN, Democratic strategist Hilary Rosen let slip that Romney's wife, Ann, is unqualified to talk about economic issues affecting women because she has "never worked a day in her life". Spotting an opening, Republicans portrayed the comment as an attack on housewives. "I know what it's like to struggle," said Ann Romney, who has raised five boys, adding that her husband often tells her "your job is more important than mine."

Prominent Democrats, including Michelle Obama, moved quickly to contain the story, disavowing Rosen's criticism, but the damage had been done. "Their 'war on women,' which was milked for weeks, is definitely no longer," said Republican National Committee spokesman Tim Miller. "They have the woman problem right now." At a private fundraiser, unaware that reporters could hear her, Ann Romney told campaign donors: "It was my early birthday present for someone to be critical of me as a mother, and that was really a defining moment, and I loved it."

Of course, as the wife of an already wealthy man who has become considerably richer over the course of their marriage, her experience of raising children is very different to that of the average mother. Staying at home was a choice that is unavailable to most poor and middle-class families, where two incomes has become the new norm.

Surveys consistently show that there is enough economic uncertainty for Romney's singular focus on jobs and standards of living to resonate, but his personal qualities leave women, in particular, cold. Almost twice as many voters see Obama as the more likeable and friendly of the candidates. Ann Romney's proposed solution to her husband's perceived stiffness and lack of empathy? "I guess we better unzip him and let the real Mitt Romney out."

In a USA Today poll released this week, women under the age of 50 in swing states favoured Obama over Romney by 54% to 36%, highlighting that this is an ongoing problem for the Republican campaign. When the same newspaper asked women what the number one issue affecting their vote is, the top response was women's healthcare.

This is often misinterpreted as a narrow focus on reproductive rights when, in fact, the broader subject that women care about much more than men is the social safety net as a whole.

"For more than a decade, women have been more likely than men to favour an active role for government," noted a Pew Research Center report released last month. "Recent surveys show that higher percentages of women than men say that government should do more for the poor, children and elderly."

The overheated "war on women" rhetoric will soon die down – in her fateful CNN appearance, moments before putting her foot in it, Rosen suggested that the phrase should be retired, once and for all. "The Obama campaign does not use it," she said. "President Obama does not use it." But, as long as Romney supports the "marvellous" budget proposed by House Republicans, which would gut the welfare state, expect Democrats to continue to remind women where the two parties stand. They will need to – among white men, according to the latest polls, Obama currently trails Romney by 20%.