There are a lot of competing numbers on the gender gap, and none of them are good for Udall. A recent Quinnipiac poll found Udall leading by four points among women — but Gardner leading by 13 points among men. Another recent poll, by the Democratic firm PPP, also found Udall up by four points among women, with Gardner leading by 11 points among men. A CNN poll more than a week ago found Udall leading by nine points among women, but Gardner leading by an astonishing 20 points among men. Any of those scenarios would be disastrous for the Democrat.

Private polling done by Republicans is a little more cautious — in the wake of the Romney loss in 2012, many GOP strategists are being extremely careful in how they read data — but still shows the gender gap working in Gardner’s favor. A Colorado GOP strategist says recent private surveys have shown Udall leading among women by between six and eight percentage points, while Gardner leads among men by between 11 and 14 points. That scenario, too, would be terrible news for Udall. GOP strategists also believe Gardner’s gap among women is slowly shrinking, while the margin in his favor among men is slowly growing.

“There is a gender gap that will have a significant impact on the outcome of Colorado’s U.S. Senate race, but it’s not what you might think,” said Ryan Call, chairman of the Colorado Republican Party, in an email exchange.