In fairness, fully 60 percent of Marines deployed in combat zones think performance would be negatively affected by letting gays serve openly. Amos’s point, I take it, is that under those circumstances any added distraction — doesn’t matter what it is — is capable of getting someone killed. I understand his concern, but he seems to have no theory of how the distraction might work in practice; beyond that, it’s hard to fathom how the most famously tough-minded troops in the world, the tip of the American spear, would be so thrown by serving alongside an occasional gay solider that it might lead to one of them getting his legs blown off. Marines cope daily with the “distraction” of seeing their best friends shot to pieces, and yet … this is going to bother them to the point of absent-minded recklessness?

“Mistakes and inattention or distractions cost Marines lives,” he said on Tuesday, explaining how he came to his decision. “That’s the currency of this fight.

“I don’t want to lose any Marines to the distraction. I don’t want to have any Marines that I’m visiting at Bethesda [National Naval Medical Center, in Maryland] with no legs be the result of any type of distraction.”…

When pressed to explain exactly what a breakdown of “unit cohesion” could look like and why it would endanger Marines in combat, or the larger war effort, Amos said he was unsure but that the significant concern of breakdown was good enough for him.

“I can’t explain what the expectations are. I can’t explain what they think might happen,” Amos said…

But with so many Marines engaged in Afghanistan, he thought about what could happen to small units like those in Sangin, where fighting is the heaviest by many accounts. When a firefight breaks out, he said, lives depend on “intuitive behavior” free from distraction.

“Intuitive behavior” is an issue in combat situations, but U.S. allies manage to do fine with gay troops and, again, Amos seems to have no theory of how troops’ intuition might be affected. Is he suggesting that gay soldiers wouldn’t rush to the aid of a wounded straight comrade, or vice versa? If the objection is that a RINO civvie like me can’t possibly understand, well, plenty of milbloggers have been on record for awhile now in favor of repealing DADT. I assume not a single one of them would take that position if they thought it would seriously risk American lives. And in fact, according to the Pentagon survey, 84 percent of Marines (overall, not just combat troops) who’ve worked with someone gay said it hadn’t affected unit morale.

Just as I’m writing this, ABC is out with a new poll finding that 77 percent of the public supports letting gay troops serve openly. I haven’t gotten here into the question of gays’ right to serve versus the military’s interest in unit readiness (Gates’s big worry is that that question will end up being decided by courts instead of Congress), but here’s an interesting data point from the American Prospect from the last time the military was grappling with questions about integration. It’s an imperfect analogy, obviously, but the Pentagon did survey troops — including “combat crews” — in 1945 about how they’d feel training in racially mixed units. Turns out that was quite a distraction at the time, too.