There is also a more nuanced ethical argument in favor of repealing DADT, which Hilzoy outlines pretty effectively here:
It has always seemed obvious to me that Don't Ask, Don't Tell is immoral and discriminatory. But I've never understood why it isn't clear that it's also an insult to the professionalism of the military. The very idea that our soldiers should not be quite capable of subordinating their personal beliefs to the needs of their unit is as insulting. The idea that if some of them can't, we should fire the people they object to rather than the ones who cannot be counted on to put their jobs first, is just bizarre.
I'm sympathetic to both of these arguments. In addition, I think that calling on some members of the armed forces to lie about their sexuality seems to (at least) violate the spirit of the Uniform Code of Military Justice.
But there is another case for repealing DADT of which I'm far more suspicious. Over the past few years, many left-wing pundits have argued that DADT is simply bad policy because it turns away good soldiers for no sensible reason. In other words, DADT has made our country less safe by effectively decreasing the size of our military.
The problem with this argument is that it doesn't allow for any consideration of the counterfactual scenario. It's undeniable that DADT has had an effect on and recruitment rates. However, if this is a primary concern for policymakers, then the real question is: How would repealing DADT impact retention and recruitment rates?
Are the kinds of men who join the military disproportionately likely to be ultramasculine homophobes? Or religious zealots? Or perhaps just strong social conservatives? If so, would these men be less likely to sign up for duty if DADT is overturned?
It's difficult to foresee a circumstance in which repealing DADT wouldn't cause at least a mild decline in retention and recruitment among certain demographic groups. But would repealing DADT make the military worse off than under current law?
I think that opponents of DADT should stick to making the moral case. Because the answers to these practical policy questions are far less clear than advocates might suggest.