Imagine if a modern senator said:
"At this moment of immense hardship for our armed services, we should not be seeking to overturn the 'Racial Segregation' policy. [It is] imperfect but effective."
"At this point there is no reason to rush to judgment for political expediency until we hear from our military leaders as to whether they think it is a good idea to change this policy [of racial segregation]."
Now replace 'racial segregation' with 'sexual segregation' and the moral reason why the current 'Don't Ask, Don't Tell' policy is incompatible with modern sensibilities is highlighted in bold relief.
The military often likes to present itself as a modern, professional organization. In private business, sexual discrimination is illegal. Those companies foolish enough to try it get sued. Why should the military be any different? Is it really too much to ask our paid, professional soldiers not to be bigots?
Those that do not like homosexuals are unlikely to change their feelings any time soon. There is no need for a transition period: end the policy now. Put the argument in racial terms and see how horrible it sounds: "our fighting men need to get used to working with [black people]."
We dishonor our military by thinking that they cannot make this change or that most would not welcome it. Who are we to turn away those who would die to defend our country?