Kevin's right. If the pundits currently lamenting the breakdown of the immigration deal could read the vote tallies, they'd realize it wasn't really a bipartisan failure at all. It was a partisan failure triggered by Republicans. As Kevin notes, "Democrats voted 37-11 in favor of moving forward to a final vote. Republicans voted 38-7 against it." One side was pushing for success, the other for the status quo. This isn't complicated.
It's telling, too, that in all the years of unified government, when Bush's political capital was at its height, there was no movement towards a comprehensive immigration solution. The Republican base simply will not countenance humane, realistic, reforms.