Flip three states that Mr. Obama carried by 3% or less in 2012—Florida, Ohio and Virginia—and he still wins, but with only 272 electoral votes, one more than George W. Bush in 2000. And, like Mr. Obama, Mrs. Clinton may have trouble with male voters. In the 2008 primaries, she lost the men’s vote by 13% to the party’s eventual nominee. Thus the Clinton campaign may feel added pressure to make sure women are in her camp.

Even if Mrs. Clinton ultimately decides not to run, any Democratic presidential nominee would be almost obliged to campaign against a GOP “war on women.” The potential reward, and the proven effectiveness of the tactic, would be too hard to resist.

So how should the GOP prepare for the “war on women” allegations to come? Here are three suggestions.

First, Republicans would do well to de-emphasize social issues. They didn’t do so in the 2012 campaign, when conservatives promoted concepts and crusades—including defunding Planned Parenthood and promoting the No Taxpayer Funding for Abortion Act—that were grist for the Democratic attack mill.