On Thursday, Defense Secretary Ash Carter announced that all combat positions without exception would now be open to women. The announcement is not unexpected, but is likely unwelcome for most in the military, as well as the general public.

“Today, I’m announcing my decision not to make continued exceptions, that is, to proceed with opening all these remaining occupations and positions to women,” said Carter. “ There will be no exceptions.”

Carter said that as long as they meet standards “They’ll be allowed to drive tanks, fire mortars, and lead infantry soldiers into combat. They’ll be able to serve as Army rangers and green berets, Navy SEALS, Marine Corps infantry, Air Force parajumpers and everything else that was previously open only to men.”

General Dunford, former Commandant of the Marine Corps and the current Chairman of the Joint Chiefs of Staff had asked for an exception to this mandate as it applied to the Marines. He was denied. He declined to attend the press conference announcing the policy change and instead he did what any good Marine would do: He issued a statement that said he would carry out this order to the best of his ability.

“In the wake of the Secretary’s decision, my responsibility is to ensure his decision is properly implemented,” said Dunford in a statement.” Moving forward my focus is to lead the full integration of women in a manner that maintains our joint warfighting capability, ensures the health and welfare of our people, and optimizes how we leverage talent across the Joint Force.”

Reportedly, this decision will open up 220,000 jobs in the military that were previously available only to men.

As a former Marine officer, I’d like to think that I have some insight to add to the discussion. I was on active duty for six years and served in Okinawa at 7^th Communications Battalion and at Marine Corps Recruit Depot, Parris Island (PI). My experience at Parris Island is most relevant to the discussion. While there I served as a platoon commander for three all female platoons and as a company executive officer (XO) at 4^th Battalion, and as company XO at Support Company (Medical Rehabilitation Platoon and Physical Conditioning Platoon) with both male and female staff and recruits.Fourth Battalion is the only female training battalion at PI, and in fact in the Marine Corps. All female recruits come to PI for training, whereas males are split between Camp Pendleton and Parris Island, depending on which side of the Mississippi they are from. At PI, the training regiment, of which 4^th Battalion is a part, includes three other male battalions. On the whole males overwhelmingly outnumber the females at PI and in the regular fleet, where they make up about 93% of Marines. When I was at Parris Island from 94-97, each battalion only had drill instructors that were the same sex as their recruits. There is some talk of changing this at present, and other services do not have this restriction.

Support Company was the place where recruits were sent if they were unfortunate enough to have an injury during training, or they needed to improve their physical conditioning in order to keep up with training. Males and females maintained separate platoons and each had their respective same sex drill instructors. At Support Company, males and females frequently trained together and of course all drill instructors, whether female or male had the power to correct, and instruct, any recruit of any sex.

It was my time at Parris Island that most informs my view of the capabilities and attributes of men and women. The question of women in combat was a question we talked about even back then, and I believed then as I do now, in equal opportunity and advancement based on merit. I also believe in esprit de corps and its practical manifestation as unit cohesion. If we need to make a choice between merit and unit cohesion, I will choose the latter, as it is the foundation of the bond between individuals that leads to success. Unit cohesion is greater than the sum of its parts. It is an intangible. Unit cohesion must win the day.

Something that has always struck me as I remember my female recruits, and my female drill instructors, was how small in general they all were. I often wondered why did the Marines attract all these tiny little girls? It was a question I got a lot myself as I too was only 5’4”, and I was quiet – not a stereotype you would peg to become a Marine. While the recruits were physically small, there was nothing little about their heart. They stood out to me as quite different from women in general, and I will say I have never felt a kinship amongst other women as I have felt when I was with other women Marines.

These females who signed up for the Marine Corps (The Marine Corps for Pete’s sake!) were simply not cut from the same cloth as the general female population. They willingly took on manly challenges and found ways to be successful, even when they might not have the brute strength to muscle through. They worked together differently than did male recruits. They tended to be more aware of their fellow recruits and offer help more readily. Their efforts were more outwardly cooperative. Their encouragement to each other was compassionate. In essence their approach to male oriented challenges embodied the best of the female attributes. And yet, while these women were uniquely gifted to meet the challenge to become a Marine, they were still not men.

The differences between the physicality of men and women are so obvious it is really shocking that we have to continue to assert this as an obstacle. At Support Company, I was able to see males and females side by side, and there is simply no amount of training that will ever bring women, on the whole, to meet male standards. There are certainly a few women who can compete with men in this department but the number is extremely small. Again this should be no surprise to anyone since we have yet to see any integrated professional sports, or male teams competing against female teams, or a gender neutral Olympic Games. If that ever happened, women would simply not be competitive. Generally, the strongest female might be about as good as the average man. But that doesn’t mean women are not valuable resources, so why not exploit the things females bring to the table instead of trying to push men aside from what they do best?

A further concern with physical differences that is evident between men and women is the types of injuries they suffer. Women incur pelvic stress fractures at a much higher rate than men. Female recruits frequently suffered this injury. It was caused by the weight of the pack and the unique structure of the female skeleton. Women cannot carry the same amount of weight as men, for as long as men, before having an injury. That’s just a fact. This particular injury is potentially career ending, and at the least can require several months of recovery.

The physical differences between men and women have been downplayed in the push to put women in combat but they are a truly formidable obstacle to integration. As I stated above, there are very few women who will be able to meet the standards as they exist today. For the minuscule number of women who can meet the standards, they will not be joining units where female strengths will be much appreciated, and this will happen even in the very best of circumstances. What I mean by this is that the way of doing things at the combat arms unit will be male oriented and it will work just fine (it will likely be based on brute strength, and other male oriented interactions). Women will attempt to do things the male way and it will not work for them. It will look like there is something wrong with the woman. This is a disservice to women – when you try to measure a woman by the standard of a man, the woman will look deficient (and vice versa). So what will happen is that accommodations will be made in order to incorporate the woman into the unit. This will result in hard feelings, resentment, and ultimately loss of unit morale.

And this really goes to the heart of the matter in my opinion: unit cohesion. Men cultivate unique bonds with each other. These bonds are not the same as bonds made between the sexes. It is the unique male bond that is the basis of esprit de corps, and embodied in the declaration, “Once a Marine always a Marine.” This bond is exceptionally important in carrying out missions relying on brute force. Those are the missions of legend – something akin to what Marcus Luttrell experienced in Lone Survivor. In situations like that it seems very unlikely that females could perform as well as or better than a man.

There are other issues that to a lesser extent will be problematic, but will also detract from unit cohesion. Romantic relationships do happen. Commanders regularly have to deal with those associated problems because their units are filled with single young people. Bringing this problem to the battlefield is unwise, so sleeping and hygiene must be separated. Once people are separated from each other, the necessary bond cannot be fully developed. If a romantic relationship does develop, it will tear at the bonds of the rest of the unit. A unit must maintain equal treatment amongst all members. When one member favors another in a romantic sort of way, it will detract from the ability of the unit to function. To fix this problem, individuals may be transferred out of the unit causing further disruption. Proponents of integration will just say everyone needs to be mature, but they ignore reality. It’s as if they have no clue about human nature and the way people interact with each – these things must be managed in order to carry out the mission. The supposed benefits of integration are fraught with real world problems that will affect readiness.

There is no doubt that there are several areas in combat oriented jobs where females can and do serve in an exceptional manner. Some of these jobs may be filled equally well by both men and women. Others may actually be filled better by women – depending on the cultural rules of the combat arena, women can be great assets to intelligence gathering and establishing relationships with local people. Using their inborn female attributes, women can analyze, plan, and shoot at a rate equal to or better than men. This opens up nearly any military job a woman would want to have. Currently the amount of combat arms jobs restricted to men is very small in comparison to jobs available to everyone (about 15%).

I believe the initial push for women to gain combat positions stemmed from the inequality in promotion opportunities. In order to build a solid promotion file, combat leadership experience was a must. Women who were prohibited from combat positions therefore did not get promoted. In order to remedy this unbalance, the promotion system should have been revised. Today, as we frequently hear, women regularly work in combat zones. This experience should count toward the combat requirement, not just the narrowly defined combat arms positions like infantry, artillery, or tanks. Leadership under stress should be the standard.

Another solution that would not threaten unit cohesion is to create combat arms units that are filled only by females. This would happen at the platoon level, and a female platoon could be incorporated into a combat arms company. I know this sounds silly but ask yourself why this is silly if the premise is that women are capable of satisfactory performance in combat arms? If a dispersed group of women can meet the standards, why can’t a platoon of women do the job too?

It also sounds like a regression of progress (because integration of everything is modern and “right”), but I actually think this would allow women to have a chance to do a job they want to do in a way that doesn’t jeopardize morale and readiness. I am sure this would never happen, because no one would take it seriously – they wouldn’t believe that an all female unit could hold their own in a combat unit – it would therefore be irresponsible to put the females in a losing situation. But depending on the mission, females might surprise everyone. I think the practical opposition to this would be that they wouldn’t have enough females to fill the positions. This fact alone should inform the policy makers that there would be a problem with integration – there’s not going to be enough women to make this work in a large scale way, and is it worth it to bring about this change for how few women will be affected? Further, it might open some eyes to the fact of their biased thinking – pairing women with men is the only way this can succeed. But if the idea is that women are capable of entering combat arms, then they should also be capable in a single sex group of performing in a manner that can rival male performance.

I don’t have any qualms about females pulling triggers or being on the receiving end of enemy fire. They are fully capable of shooting straight, and effectively, and being equally proud of enemy kills. I don’t give much credit to the idea that females face worse treatment when they become prisoners of war. Torture is torture. I acknowledge some females will be able to compete satisfactorily with regard to the physical standards, but the number of females to whom this applies is so low that it makes little sense to integrate them into male units. It doesn’t mean they cannot perform in the combat zone as well as in some combat jobs, but the line should be drawn where integration affects unit cohesion.

Unit cohesion, the thing that wins battles, should not be compromised in an effort to accommodate ideals of gender equality. The promotion process should be reviewed to ensure it gives appropriate weight to performing well regardless of the military specialty. If there were a way to integrate combat arms without destroying uniquely valuable male bonds that allow for successful combat missions, it might be done, but there is no way to add women to the mix without damaging this incredible necessary attribute of all-male units. Women in combat advances a flawed ideological agenda and will not enhance the capabilities of our fighting forces.