Well, yeah ... but that's just the problem, isn't it? The immigration debate is currently controlled by those on both sides who yell the loudest. There's no room for rational thought, much less rational action.
Deportation is the only rational thought. The course of action can be debated, then swiftly acted upon.
If the rule of law means anything, then it must be enforced and not changed after it has been broken, or it means nothing at all.