I know the argument regarding third parties, but in this case I just don't see it. And, trust me, I like to look out for things that will help third parties

Yes, more undecided people can vote third party with same day registration, but they can also vote democrat or republican. Really, I don't think undecided voters really have any more of an inclination towards third parties than toward the two major parties.
Of course, whether it TRULY helps third parties doesn't matter I suppose. If the two major parties think it will hurt them, then they'll prevent it from happening.
We REALLY need a constitutional amendment taking control of elections away from the people who receive votes
