Here's how I see it:
Hillary pretends to be conservative on this issue and rides it to victory. Of course she will never make good on any of her faux-conservative positions. We Lose.
Hillary runs with this issue and loses. Rove and the country club Republicans makes the case that illegal immigration is a loser issue and relegate people calling for enforcement as xenophobes, racists, nationalists, etc. Again we lose.
How true.