People often presume that the "gender gap" in voting behavior is driven by differences of opinion on "women's issues" defined in a very narrow way. But I think that one valuable insight that falls out from the controversy over whether or not a married stay-at-home mom like Ann Romney has ever "worked" is that questions of family structure are intimately linked with questions about tax and spending policy. Note, for example, that Mitt Romney has a very different view about working moms when it comes to low-income unmarried women:
“I wanted to increase the work requirement,” Romney said. “I said, for instance, that even if you have a child two years of age, you need to go to work. And people said, ‘Well that's heartless,' and I said ‘No, no, I'm willing to spend more giving daycare to allow those parents to go back to work. It'll cost the state more providing that daycare, but I want the individuals to have the dignity of work.’”
The phrase "the dignity of work" is extremely condescending and ignores precisely the point the Romney camp was trying to make about Ann Romney—unpaid household work is still work and it's still hard. At the same time, there is a sound policy point behind Romney's argument about the desirability of pushing welfare recipients into the labor market. The issue is that when you work in the paid labor market you not only obtain income, you obtain job skills and connections that help you obtain further income in the future. This skill-building is both personally and socially valuable, and it explains why it can make sense for the public sector to expend funds on helping connect people with paid employment even when simply cutting them a check would be cheaper.
But the same consideration applies to married women! Today's married mother, after all, may be tomorrow's divorced mom. If you stay out of the labor force while married, this will severely hurt your earnings prospects if you become single. And the fact that you'll be hard-pressed to cope with the economic consequences of divorce weakens your bargaining position within the marriage. Indeed, Torben Iverson and Frances Rosenbluth argue in a fascinating paper on "The Political Economy of Gender" (PDF) that this has what's driven women to left-of-center political parties in a wide range of advanced economies.