Republicans are likely to nominate women in four of their top-targeted Senate races this year -- something they hope helps them appeal to elusive female voters and close the so-called "gender gap."
But if history is any guide, they should keep expectations low. In fact, recent elections with Republican women candidates have wound up with very average gender gaps on Election Day.
First, a little historical refresher. While much has been written about the Democratic accusations of a GOP "war on women" and how Republicans are struggling with women, there is very little evidence to suggest this is some kind of new phenomenon.
Since 1980, presidential campaigns have on average produced a 15-point gender gap. That is, the difference between Democrats' advantage among women and Republicans' advantage among men is generally 15 points. So, for example, Democrats win women by 8 points and Republicans win men by 7 points: 8+7=15.
Here's how that looks:
In 2012, Mitt Romney's gender gap was 18 points (+7 among men, -11 among women) -- again, not that far off the average -- and the average gender gap in Senate races was 17 points.
Now, using 15-17 points as the baseline gender gap, we looked at eight marquee Senate races between 2006 and 2012 in which Republican nominated a female candidate.
According to exit polls and the last available pre-election polls (where exit polls were not available), the average gender gap for women in these eight races was ... wait for it ... about 15 points (14.5, to be exact).
In addition, with the exception of Katherine Harris's huge loss in Florida in 2006 (in which she was widely disliked), none of the eight women have narrowed the gender gap even to single digits. The closest was former Hewlett-Packard head Carly Fiorina in the 2010 California Senate race. According to exit polls, Fiorina lost men by 3 points and women by 14 -- an 11-point gender gap.
Now, eight races is not a huge sample, and things could change with a larger data set. We wish there were more data, but Republicans nominate far fewer women for high office than Democrats.
There is a little good news for Republicans, though, and that is that their current crop of women appears to be running ahead of the traditional gender gap -- at least according to the most recent polls.
But these are early polls, and history suggests it will be hard for them to maintain such tight gender gaps.