Senate block - John Hawkins has the inside story how the immigration bill was killed in the Senate from a Washington source:

I asked my source if his boss has been hearing from his constituents on this bill and what the for and against ratio was. He said that they have received thousands and thousands of calls and the ratio was something like 95%-98% against the bill.

Vox populi, eventually.

Update (6/9) - Rassmussen Polls reports that the Senate bill had virtually no support.