Obama didn't say that he will enact CIR when the borders are fully secured. What Obama and Napolitano said is that they have to show that THEY can enforce the law, the law that could come when CIR passes. its not like ICE will have nothing to do. All Obama wants to do is show efforts on securing the border, showing progress toward doing it, so the opposition says "look the border is more secure and is gonna get even more secured"...

they will always have some to argue on, but "secure the border" is their strongest argument.