Easy one - who're they catering to?

Democrats are currently deciding basically between Hellary and Obama - both of which are MAJOR antis. It is no surprise that they decided to push a piece of legislation likely to help the campaign of either one.

Unless the Republicans as a block, or at least most of them, had voted against, there was no way any more sensible Democrat would've voted against. The cost would be too high within their own party. But the cost for ANY Republican was too high to vote against too: "law and order" and, for the fundie sectors at least, "moral issues" are one of the few areas where the Republicans are still more credible than the Democrats - and this piece of legislation can easily be sold to voters with strong leanings on those two issues.

Indeed, a beautiful act of corrupt parliamentary practice.