The vote to repeal DADT (Don't Ask, Don't Tell) just failed to pass the Senate, despite the fact that recent polls show public opinion as being 75% in favor of repeal. 56 Senators, all Democrats, voted for repeal and 43 voted against - all of the Republicans and the two Democrats from Arkansas. A lot of people see this as a failure of the Obama administration - if they can't accomplish something they specifically promised to do in 2008 and that has 75% public support, what can they accomplish? And it is a failure, to tell you the truth. DADT is horrible. However, I'm not sure I agree that the blame for not getting this done belongs at Obama's feet.
The first thing you have to ask when you hear that 75% of people are in favor of something is how much they care. (I think there's an episode of The West Wing that I should be citing for this tidbit of wisdom, but I'm too lazy to figure out which one). On DADT, my guess is that it would be a very small portion of the 75% that care very much. People care passionately when you raise their taxes, or take away a service they rely on. In comparison, DADT exists in an ideological wasteland. Most people aren't gay, and most people don't want to join the military. Many of the people who strongly identify with gay people don't strongly identify with wanting to join the military, and vice versa.
It certainly makes sense to me that the offices of 41 Republican Senators, and 2 Democrats, could have come to the conclusion that it was safe and even preferable for them to go on the record against this hugely popular repeal. You have to consider the states they come from - I only know so much about Arkansas, but I'm willing to bet that public opinion there is a little bit less than 75% in favor. You have to consider their political party - an incumbent Republican Senator's reelection strategy is going to depend primarily on holding onto the same voters as he got last time around, and he already knows those people are pretty flexible about supporting a party that is perceived as anti-gay, whether they belong to that 75% or not. And you have to consider the opposition - we know that that other 25% includes a lot of people who are passionate; in their belief that the military belongs to them as a symbol of what real American patriotism looks like, or in their conviction that traditional Christian doctrine is as fundamental to this country as the constitution, or in their desire to stick it to Obama any chance they get. 41 Republicans and 2 Democrats decided that those were the people who were going to care how they voted on DADT, and politically speaking, they were probably right.
I'm not really sure what the administration could have done about that.