If this man is killed, Obama will say it was because of his support for SB 1070. And that Enforcing immigration law is impossible.
If he actually was stupid enough to say that, he might as well say "I will not be seeking reelection."
He will never say that.
Moreover, I seriously doubt the cartels are stupid enough to order the assassination of an American LEO.
That's the last thing they need - it would be much cheaper in the long run to find another sheriff who can be bribed.
If he is killed, then the Federal Government has “officially” failed to “...protect them from invasion...” and its time to bring the all NG home to the job the Feds won’t.