It’s a question that’s remarkable for its absence in the Democratic primary season: Is a woman capable of being president? Sen. Hillary Clinton’s candidacy raised a lot of questions, renewed some old criticisms and stirred plenty of new debate, but her fitness for the job, based on her gender, was never seriously questioned. That’s a milestone worth noting.

In her speech Saturday formally endorsing Sen. Barack Obama for president, Sen. Clinton referred to the barrier that women have bumped up against as they try to rise in the political realm: “Although we weren’t able to shatter that highest, hardest glass ceiling this time, thanks to you,” she told supporters, “it’s got about 18 million cracks in it,” a reference to the number of votes she landed.

Twenty-four years ago, Democratic presidential nominee Walter Mondale named Geraldine Ferraro as his vice-presidential candidate. After getting an early bump in the polls from the choice, the Mondale-Ferraro ticket got a shellacking at the hands of the incumbent, Ronald Reagan, that November. Forty-four years ago, Margaret Chase Smith, the Republican senator from Maine, was the first woman to actively seek the presidential nomination. The GOP nominated Barry Goldwater instead, who lost to Lyndon Johnson.

Maybe because Sen. Clinton was such a well-known commodity, with proven leadership skills, political toughness and more than her share of controversial baggage, few seemed to wonder whether a woman was temperamentally suited to the job. Instead, the questions were about the role her husband Bill would play, whether she was capable of candor, and how partisan she would be if elected.

Not everyone who would question a woman’s suitability as commander-in-chief should be dismissed as sexist. Sen. Clinton invited such questions when she teared-up during a campaign stop in New Hampshire; would a woman president get weepy about military threats, inhibiting her ability to respond firmly?

Clearly, men and women have different emotional responses in different situations. One might argue that men are better able, generally speaking, to set aside emotions and act. But the counter argument is that women are less prone to macho posturing, a response that could easily escalate into war.

The world has had enough examples of strong, decisive national leaders who happen to be women to disprove the stereotypes: Elizabeth I and Margaret Thatcher of England, Indira Gandhi of India, and Golda Meir of Israel. It’s not hard to imagine a President Hillary Clinton with a tough-as-nails response to a Hurricane Katrina or Sept. 11. And as Sen. Clinton said Saturday, that threshold having been cleared, the next woman who seeks the White House will have a slightly easier journey. For that, every woman – and every man – should be grateful.