Is there any chance this could actually happen? This would destroy Democrats. Not to worry however. Obama can claim the Republicans are trying to disenfranchise voters, then issue an executive order to prevent it.
I think that's a great argument in our favor. In many states elections are controlled by one or two urban areas while the rest of the state is disenfranchised. Washington, where I live in an example of this. It was considered a deep blue state with 12 votes going to Obama in a winner take all contest when in actuality only 4 congressional districts were solid blue, two were pretty close and 6 were red. In a proportional allocation those 6 red votes would have gone to Romney. Even though those districts vote republican, many people don't bother to turn out because they know we are controlled by three urban counties and most of the state votes don't matter, except for local offices.