Nearly a generation ago, MSNBC’s Chris Matthews coined a description of our two political parties that may turn out to be his most enduring contribution to American punditry. Republicans, Matthews wrote, were the “Daddy Party,” all about military security and self-reliance; Democrats were the “Mommy Party,” all about health, education and nurturing.

At the time, in 1991, Democrats weren’t sure they considered that much of a compliment. Since then, a long line of Democratic presidential candidates — including one who is an actual mommy, Hillary Rodham Clinton — have taken pains to prove they could be as tough and decisive as any stereotypical Mad Man.

But this year, facing an uphill battle to retain their majority in the Senate, the Democrats have decided to embrace the label as a badge of honor, making a strong appeal to women — especially working mothers.

Democratic campaign rhetoric this year bristles with female-friendly ideas. The party hasn’t merely reprised its long-standing endorsement of abortion rights; it’s also calling for pay equity for women, stronger protections for pregnant women in the workforce, broader paid sick leave and family leave measures and universal early childhood education.

The point of these ideas is to send a message to female voters — especially unmarried women and working mothers  — that the Democrats are on their side.

“When women succeed, America succeeds” was one of President Obama’s applause lines in his State of the Union address, and he’s repeated it frequently since. This spring, Obama plans to host a Working Families Summit at the White House to promote many of the same ideas.

Democrats have long cast themselves as champions of women’s rights, especially reproductive rights. But the unabashedly woman-centric emphasis of this year’s campaign is unusual and largely based on electoral arithmetic.

Democratic strategists have calculated that if unmarried women vote in great numbers, the Democrats are likely to retain their majority in the Senate. If unmarried women stay home, Republicans will probably win the six seats they need to take over.

In midterm congressional elections, winners are more likely to be determined by which voters turn out than by which party is more popular. In the 2008 presidential election, about 131 million people voted; in the 2010 congressional election, only 95 million voted — a drop-off of 36 million.

That drop-off meant the difference between a Democratic victory (in 2008) and a Republican triumph (in 2010). The voters who didn’t show up, as is often the case in a congressional election year, were disproportionately Democratic, including millions of young people, minority voters and unmarried women.

GOP leaders have even organized a program, led by Katie Packer Gage, to train candidates to frame their conservative message in a female-friendly way. It’s designed partly to protect the party from the problem it ran into in 2012, when Rep. Todd Akin, R-Mo., a candidate for the U.S. Senate, declared that women who were victims of “legitimate rape” could not become pregnant, and several other GOP candidates defended him.

Packer Gage said she couldn’t guarantee that no Republican candidate would again wade awkwardly into reproductive issues. But next time, she asserts, GOP leaders will do a better job of containing the damage.

That may be a tall order. Democrats openly admit that they’re praying for more gaffes from conservative candidates. Last month, when Steve Martin, an obscure Virginia state senator, referred to a pregnant woman as her child’s “host,” his comment instantly became fodder for Democratic fundraising pitches.

Doyle McManus is a columnist for The Los Angeles Times. Readers may send him email at [email protected].