What killed the Senate immigration bill?

Jack Hawkins says he has the inside story.

And here's the NYT report:

The outcome, which followed an outpouring of criticism of the measure from core Republican voters and from liberal Democrats as well, was a significant setback for the president. It came mainly at the hands of members of his own party after he championed the proposal in the hope of claiming it as a major domestic policy achievement in the last months of his administration.

We're down to the "last months" already?