In reading through personal letters written during the Civil War, historian Drew Gilpin Faust noticed a profound difference between the preoccupations of men and women, regardless of whether they supported the conflict.

In their letters, the men talked of war in terms of glory, politics, victory. For the women, the war was about one overriding concern: death.

A century and a half later, despite all the advances women have made in the military and government, they remain at times of war the anxious sex. Concern for the safety of loved ones and fear of what dangers war will unleash trump all else.

Don’t be fooled by the talk-show chatter and snapshot poll results suggesting that the gender gap in support of the war with Iraq is narrowing. It is. But the worry gap remains as strong as ever.

Read the fine print of those poll numbers, and it is clear that women are more worried about this war. They are more afraid. They are less confident about the outcome. They are less willing to trust that the United States will be successful in removing Saddam Hussein from power, and are more likely to predict that the number of casualties will be high.

While a majority of men believe that this war will make the nation safe from terrorism, a majority of women do not.

The political ramifications of this persistent gap cannot be dismissed. George W. Bush lost women voters by 11 percent in 2000, and surely strategists in both parties are waiting to see whether this war puts a dent into that dynamic.

Not for nothing do we say that men are from Mars and women are from Venus.

The terrorist attacks on Sept. 11, 2001, were expected to have changed the attitude of women toward war, just as they altered so many things in American life. Until then, of course, support for military action broke down along gender lines as predictably as laundry duty.

After the nation was attacked — and the workplace became a battlefield, and airplanes became weapons, and civilians became soldiers — women were as likely as men to support military retaliation. The reality of war on these very shores aroused similar desires to protect and defend — and, perhaps, revenge.

The repercussions of that onetime shock to the national psyche continue today, as bombs fall over Baghdad and troops storm across the Iraqi sand. Women still don’t support this war as much as men do, but the gender gap is narrowing. When asked by Gallup last week whether they favored invading Iraq with ground troops, 70 percent of men and 60 percent of women said yes.

In answer to a similar question posed just before the first Gulf War in 1991, 76 percent of the men approved, but only 54 percent of the women.

In a military where women now make up 15 percent of the active-duty soldiers, in a nation where the national security adviser is a woman, war may no longer be the sole province of men. Nonetheless, worry is still a woman’s lot.

Here is just one example from a ream of data collected in Gallup’s national polling last week. When the question was, “Does the possibility of going to war in the next few days make you, personally, feel afraid?” the nation was split. The sexes were not.

Yes: Total, 48 percent. Men, 31 percent. Women, 64 percent.

No: Total, 51 percent. Men, 68 percent. Women, 35 percent.

Janna Malamud Smith, a psychologist and author, says it’s the same way a mother goes berserk when the baby spikes a fever, while the father responds with an “It’s OK, dear.” The worry/work divide may not be biologically determined, but it is ingrained in our culture.

“Women get habituated to think about human safety. It’s more immediate for us to feel the risk,” says Smith, author of the new book “A Potent Spell,” which examines why nothing seems to lower the anxiety level of mothers. “We are in the habit of keeping a person alive.”

Men are not allowed to express these worries, at least not too much, especially if they are in positions of authority, and especially during wartime. It is not manly to be fretful. Faust, a former University of Pennsylvania professor who is now dean of the Radcliffe Institute of Advanced Study, says the same social pressure seen in Civil War times persists today.

“Women thought about death because they had permission to think about death,” she says. “They were allowed to raise issues of human vulnerability. Men were not.”

Whether the after-effects of the women’s movement will alter any of these psychological generalities, we do not know. Michael Barone, the political demographer, says that he has tracked shifts in women under 30, who tend not to be as defensive — and in many cases, as liberal — as their mothers.

Will they be as risk-averse? Will they be as pessimistic about military action? Will they trust more in technology, rather than talking, to solve the world’s problems?

It may be that this division of worry, this anxiety gap, is in fact a survival mechanism, a way to balance the competing — and at times antithetical — impulses of human behavior, to fight and to nurture, to act and to worry, to realize that there are many routes to safety and freedom.

“As long as women feel a special responsibility for family,” says Faust, “the issues of death and harm will hold a high place in their minds in terms of war.” At times like these, I can only say: May it always be so.