For years Democrats have claimed a “gender gap” advantage over the GOP because women tend to support their party’s candidates in disproportionately high numbers. The last two presidential elections clearly illustrate this pattern. In 2008, Obama ran nearly even with John McCain among men but captured female voters by a whopping 14 point margin. And in 2012, while losing male voters to Mitt Romney by 8 points, Obama’s 12-point margin with women guaranteed his re-election.

But it turns out that Republicans have their own version of the gender gap. The basic idea is to substantially out-perform the Democrats among men while reducing the Democrats’ lead among women to single digits. And they’re attempting this feat against Hillary Clinton, whom Democrats hoped would galvanize female voter support to unprecedented heights. Instead, polls reveal that Clinton is substantially under-performing with men and women alike, a trend that could well deliver the White House to the GOP.

How do we know that the gender gap is shifting? Consider the results of recent head-to-head polls between Clinton and her GOP opponents. These are not actual election results; they are snapshots of ongoing trends. The numbers may not be precise, given the margin of error, but their general magnitude and broad direction are still highly suggestive. What do these polls show?

Using the last four national polls as a statistical benchmark, and averaging the results, the following gender breakdowns were recorded for each GOP candidate in a hypothetical head-to-head contest with Clinton:

GOP Candidates vs. Hillary Clinton

Men Women Net

Rubio +12 -8 +4

Cruz +10 -9 +1

Carson +12 -12 0

Bush +9 -12 -3

Trump +6 -15 -9

As indicated, at present, there is a sharp disparity in male and female voting patterns for Clinton and her GOP opponents. The gender gap is roughly 20 points, on par with the historic level achieved in 2012. However, in the case of Rubio and Cruz, the gap is in the GOP’s favor. Why? Because their advantage among men exceeds Clinton’s advantage among women. Rubio, in fact, has opened up a 4-point gender advantage over Clinton. That’s the same advantage that Obama enjoyed when he bested Romney in 2012.

[dcquiz] How big a gender advantage does a GOP candidate actually need to win? In 1968, Richard Nixon defeated Hubert Humphrey with no gender advantage – his 2-point lead among men was matched by Humphrey’s 2-point lead among women. And in 2000, George W. Bush defeated Al Gore even though Gore enjoyed a 1-point gender advantage. (Bush led Gore by 7 points among men while Gore beat him by 8 points among women). In general, as long as the national electorate is split fairly evenly between the two genders – women have comprised 53 percent of the electorate since 2004 – breaking even or enjoying just a slight gender advantage could tip the election in the GOP’s favor. Rubio’s current 4-point advantage is undoubtedly enough to win. So is Cruz’s 1-point advantage. Even Carson might best Clinton if he were to continue to break even. Trump, on the other hand, displays a 9-point gender deficit with Clinton, which could well doom him in 2016.

There is reason to believe that the current gender gap is actually larger than these margins. That’s because of the unusually sharp differences in the favorability ratings between Clinton and her GOP opponents. Consider one recent poll. Clinton’s favorability rating was deeply negative with men (-29) and only slightly positive (+9) with women. By contrast Rubio, alone among Republicans, had a positive favorability rating with both men (+16) and women (+4). Cruz also had a positive rating with men (+9) and just a slightly negative rating with women (-5). The magnitude of these disparities suggests that the gender gap between Clinton and Rubio and Cruz may be even larger than their head-to-head match-ups reveal.

One final note: the vast majority of voters tell pollsters that they have already made up their mind about Clinton and Trump; less than 10 percent say they don’t know how they feel. By contrast, nearly 40 percent of women and over 25 percent of men in the above-cited poll say they haven’t made up their mind about Cruz, Rubio, or Carson. Given time, all three candidates might well consolidate or extend their current gender advantage. It’s up to the Democrats to try to reverse this trend.

Right now, Democrats seem content to try to tie Trump to the rest of the GOP field in the hopes of tarring his rivals with the same brush. And Trump, by all appearances, has no compunction about playing the role of Democratic whipping boy, even if it’s costing him dearly with most voters. But Trump’s GOP rivals, most of whom have distanced themselves, don’t appear to be suffering much. And they are unlikely to pay a price for his antics once the general election campaign begins.

Could Clinton regain the gender advantage if Trump winds up the nominee? Many Democrats seem to not-so-secretly hope for that outcome. But the most recent Rasmussen poll released this week suggests that Trump also may be closing the gap. Men favored him by 10 points over Clinton. However, women favored Clinton by just 11 points – far less than in previous polls.

If the GOP’s enfant terrible can achieve this kind of breakthrough, imagine what his more mature rivals might achieve.