Conservatives often stand accused these days of standing outside the "reality-based community." Yet liberals can be blinded by ideology, and nowhere is this more true than in the debate over women in combat.

Over the past two decades, the United States has moved steadily to open all military roles to women. Last month, departing Secretary of Defense Leon Panetta removed the last barriers. Women may henceforward qualify for every duty, including combat infantry. The few - very few - public objections raised to this decision were met with derision rather than argument, well represented by this sneering item from the Daily Show.

Yet to deny the highly combat-relevant differences between the sexes is to deny reality as blatantly as ever done by any anti-evolutionist - and with potentially much more lethal consequence.

In 2007, Kingsley Browne gathered the evidence in a clear and concise book, Co-ed Combat: The New Evidence That Women Shouldn't Fight the Nation's Wars. The case presented by Browne won't come as news to any military decision-maker. But it will and should jolt those who have relied on too credulous media sources for their information about what soldiers do and how they do it.

The case for women in combat runs more or less as follows:

1) We have entered an era of push-button war in which purely physical strength has lost much if not all of its military relevance.

2) To the extent that strength continues to matter, some women can meet requirements and should be given a chance to qualify.

3) Other than physical strength, there are no militarily relevant differences between men and women.

4) To exclude willing women from military service is unfair and unjust.

Browne demolishes these four claims, step by remorseless step, with studies and examples drawn from military experience.

1) Physical strength continues to matter in warfare. Soldiers still must hoist heavy packs and march for miles. Soldiers still must be prepared to function with reduced food and water. Soldiers must still sometimes fight and kill their enemies hand to hand. And even in other contexts where strength seems obsolete, the mischances of war can suddenly thrust soldiers into situations where strength determines who lives and who dies. Browne reminds us of the 2001 encounter between an American EP-3E surveillance aircraft and a Chinese "Finback" fighter jet. The EP-3E is a big plane, powered by four turboprop engines and carrying a crew of 24. The much faster Finback harassed the EP-3E with mock interceptions.

On his last approach, [the Chinese pilot] comes too close. He pitches up to maintain his slow speed, and one of the EP-3E's propellers strikes his plane at the junction of the vertical stabilizer and the fuselage, sounding "like a monster chain saw hacking metal." The propeller cuts the Finback in two. The fighter's nose flips up and strikes the nose of the American plane, knocking off the large fiberglass nose cone containing the weather radar. The immediate decompression of the cabin is deafening.

The EP-3E immediately flips over into a nearly completely inverted dive. "This guy just fucking killed us," [Captain Shane Osborn] thinks, as he is looking up at the sea below and observing that his plane is falling almost as fast as the wreckage of the Finback. The lumbering EP-3E, which is a converted Lockheed L-188 Electra passenger airliner, has never been rolled and never recovered from an inverted dive.

Using "every ounce of strength" in his muscular frame, Osborn struggles to bring the wings level. Gradually, he is able to gain airspeed and recover from the roll. The plane has fallen almost 8,000 feet from its original altitude of 22,500 feet in about thirty seconds and is still losing altitude.

(LOC 1352-1359)

Osborn eventually brought the plane to an emergency landing on Hainan Island and succeeded in destroying the plane's computers before Chinese forces arrived. He won the Distinguished Flying Cross for saving his plane and crew.

As Shane Osborn's experience reveals, strength is not irrelevant to modern aviation. Although it is not usually an issue in flying modern airplanes under ordinary circumstances, when things go wrong the situation can change dramatically. In the words of the principal investigator of a study of strength requirements of aviators, "If they lose hydraulics or an engine or two engines, it gets really tough to fly the plane."

(LOC 1376)

Strength matters too for a grounded helicopter pilot or a captured aircrew. Browne notes that about 90% of the prisoners of war held by North Vietnam were downed pilots and aircrew.

The United States is planning its future air force on the assumption that future aircrews need not worry much about enemy fire. That's a very dangerous assumption.

2) One might answer: "Fine. Strength matters. But why should gender matter? Set strength requirements, run the tests. If the women pass, they pass. If not, not."

But that answer ignores the bureaucratic realities. The record shows that the military does not and will not enforce gender-neutral standards.

[A]t the time of enlistment, a seventeen-year-old female is expected to do thirteen push-ups, compared to thirty-five for males, while for forty-one-year-olds, the numbers are six and twenty-four, respectively. A seventeen year-old girl is expected to run two miles in nineteen minutes, forty-two seconds or less, which is twelve seconds more than a forty-one year old man gets. A forty-one-year-old woman has to "run" two miles in twenty-four minus and six seconds, almost five minutes more than a man receives. Only in combat, it seems, will demands on the sexes be equal ….

(LOC 399-403)

The military executes missions, and the generals and admirals understand that one of their most important missions - from the point of view of their personal advancement - is to recruit sufficient numbers of women to please their political masters. The only way to achieve that mission is to operate very unequal standards. Browne again:

The probability that a randomly selected man will have greater upper-body strength than a randomly selected woman is well over 95 percent.

(LOC 432)

The army's standard fragmentation grenade has a blast radius of 15 meters. Infantrymen are required to demonstrate the ability to throw a grenade 35 meters; military women, only 25 meters. In practice, many military women cannot throw even that far. Browne tells the story of a Sergeant Leigh Ann Hester and squad leader Timothy Nein who came under attack in Iraq. Both won the Silver Star.

Hester gave her grenade to Nein because he "had the better arm." She did, however, throw one about fifteen yards, which, depending upon cover, may be a little close for comfort …. Even if two men had been involved, of course, one might have given a grenade to a comrade with a better arm, but the soldier with the better arm in a mixed-sex pair will almost always be the man. If both members of the pair are women, their ability to throw a grenade where it is needed will be substantially limited.

(LOC 1132-1139)

The sexes differ psychologically as well as physiologically. Women react to threat very differently from men. It seems painfully obvious to say this, but the sex hormones testerone and estrogen push the sexes to behave radically differently. Many young men will risk death rather than be seen by their peers to flinch from a fight. Women's courage takes very different forms. Browne amasses a battery of stories of military women behaving in ways that, had they been men, would have brought accusations of dereliction of duty - or worse.

During the 1989 invasion of Panama,

CBS News reported that two female truck drivers had tearfully refused to drive troops to the scene of fighting, prompting an Army investigation. Two days into the investigation - and several days before it was completed - the Army announced that the women had acted appropriately. According to Army spokesmen, the two women were "exhausted" after driving under fire for nine hours …. According to officers of the infantry battalion whose soldiers were supposed to be transported, however, the women had not been driving under fire for nine hours. They had come under fire briefly in the first hour of the invasion and then spent eight hours waiting for their next mission, at one point having to be rousted from their barracks and made to stay with the trucks. ... [Quoting another author, Browne adds] "The men at the scene had no doubt but that the women were afraid, not tired."

(LOC 1895-1902)

Sex integration has tangled the military in double standards and collective denial. The Army, Browne reports, maintains an unofficial policy whereby women - but not men - showers in the field every 72 hours. This practice is not written down, but it's observed by the troops as another example of a demoralizing military culture of denial and lying. Browne quotes interviews of enlisted men by military sociologist Laura Miller:

"Today all you hear in the Army is that we are equal, but men do all the hard and heavy work whether it's combat or not."

"The majority of females I know are not soldiers. They are employed. Anything strenuous is avoided with a passion. I would hate to serve with them during combat! I would end up doing my job and 2/3 of theirs just to stay alive."

(LOC 3644)

More cutting still, Browne repeats a bitter military joke that true equality will arrive - not when women receive Medals of Honor (since it will be suspected that the standards were bent in their favor) - but when women "can be subject to a court-martial for cowardly conduct."

(LOC 1844)

3) The most fundamental differentiator between men and women of course is mutual sexual attraction. That fact has become an increasing source of weakness to US military units, and will weaken them still further when full combat integration is achieved. Where men and women are put together, sex will follow. So will pregnancy - which is of course grounds for removing women from active duty. Sex is sometimes consensual. It is is sometimes coerced. And it is sometimes sold.

[P]rostitution by female personnel appears to be a widespread phenomenon, although the Pentagon's reticence on the subject makes it difficult to ascertain just how widespread. I have heard from numerous sources claiming personal knowledge (not as customers, they all assure me) of prostitution rings in the Army, Navy, Air Force, and Marines. I have heard it from officers who were responsible for discipline and from enlisted men who were aware of the women to go to.

(LOC 3507-3510)

The most dangerous consequence of sexual attraction, however, is the corrosion of unit cohesion. A "band of brothers" pretty quickly degenerates into a snarling pack of primates when the brothers begin to compete amongst themselves for the sexual attention of a much smaller number of women.

4) It is on the point of "fairness" that Browne expresses himself most scathingly. It's not the military's job to be "fair." It is the military's job to win wars. Our society values freedom of speech. It values the right to elect leaders. It values individual choice and market competition. All of those values are suspended in the military, sacrificed to the paramount need for military effectiveness. Yet on gender issues, the military seems to have decided that the desire of a relatively very small number of female officers to reach the highest levels of command trumps the necessities of national defense.

Ironically, the motive that most impels women into combat - the eagerness of some female officers to ascend to higher levels of leadership - is precisely the end that may be most unobtainable. A battery of studies cited by Browne confirms the reluctance of men to accept female leadership when the shooting starts. This reluctance actually increases the more that male soldiers experience female leadership, for reasons hard-wired into the male brain. Psychologists find that women's leadership is accepted by men (and women!) to the extent that it is warm, nurturing, and participatory: in other words, maternal. It is least accepted when it is cold, challenging, and hierarchical: in other words, paternal - or in other other words, military. Which means:

Military women may be in a bind. The leadership role calls for an authoritarian style, but when women act accordingly, they tend to be negatively evaluated and therefore less effective.

(LOC 2656)

Is the unwillingness of men to follow women into battle "unfair"? What does that question even mean?

[T]he measure of a leader lies not in the leader's behavior but in the behavior of his subordinates. If potential followers will not follow a leader for whatever reason, the leader cannot be effective. Whether blame is assigned to the failed follower or the failed leader is immaterial. If the mission is not being accomplished, the unit is ineffective.

(LOC 2680)

Browne stresses: "one may challenge the policy of sexual integration without disparaging the service of military women. Those who are serving now, and those who served in the past - not to mention those who will do so in the future - deserve the thanks of a grateful nation." (LOC 32)

Too many draw an analogy between sex distinctions and the military's discredited history of racial discrimination. Browne urges us to think of sex as a distinction more like age.

[W]hat would happen if the United States had fifteen thousand sixty-year-old men in Iraq and Afghanistan instead of fifteen thousand women. If it did, many of these older men would undoubtedly behave bravely. Would these stories be persuasive evidence that the military should allow sixty-year-olds to enlist? Not at all. The relevant question is whether the sixty-year-old men are as effective in combat as twenty-year-old mean, and few would be (or be expected to be).

(LOC 3943)

Co-ed Combat depicts a country that seems to have made up its collective mind that it need not worry about ever again fighting a major war against a capable enemy - A country so confident in its margin of superiority that it can afford deliberately to weaken its own military performance for reasons of pure ideology. And this time it is the so-called progressive side that treats facts as unwelcome intruders.

Sara Lister, [the Clinton-era] Assistant Secretary of the Army for Manpower and Reserve Affairs, candidly stated that the Army does not publicly discuss strength and pregnancy issues because "those subjects quickly become fodder for conservatives seeking to limit women's role in the Army."

(LOC 3831)

Well, yeah. But if your preferred policy can only be advanced by concealing relevant facts, isn't that a blaring warning of a bad policy? A big, rich country like the United States can afford many mistakes. But in this case, the mistakes will exact a cost in lives sacrificed and - very conceivably - future battles lost.