You are right, George Bush made clear in his words that he was no conservative. And so his current passion for pushing his "comprehensive" immigration reform is not a betrayal of his conservative pricipals because he has no conservative principals.
Well I think his proposal does not violate conservative principles. However, I know many agree with you. But I have to think that the 90 percent of what he said on other issues is pretty conservative regardless of ones viewpoint on illegal immigration.