I just noticed these numbers in a tweet from Reed Richardson. They're from July 17th thru 21st.
The Senate GOP desparately wants immigration reform to pass. They already helped pass it out of the Senate. The House GOP despearately wants to kill it but their strategy revolves around framing someone else for the killing - namely the Democrats or President Obama. And the main angle is hanging it on insufficient 'border security', even though the Senate bill is already largely a pork bill for companies that sell border security services and hardware.
But as you can see, that's simply not going to happen. If reform goes down, voters will overwhelming blame Congressional Republicans. By another big margin, they don't find the 'border security' excuse believable.
You can see in the box labeled June 2006 that the polls helpfully noted the contrast to 2006, the last time the general sort of Comprehensive Immigration Reform type bill went down. Back then the public apportioned blame to everyone, almost in equal measures. The issue simply had little partisan valence.
This is why Republicans who are concerned with the party's ability to win elections outside of heavily gerrymandered white districts are so worried. These numbers show quite clearly that while the bill is pretty much the same, the politics are not remotely the same. Killing reform will tighten the lilly-white straightjacket Republican strategists believe will make it hard to win presidential elections and even many Senate elections in the future.