Q: I've been deferred from early decision to regular decision. Can I apply ED2 to my second choice?
A: Yes! When a college does not accept you via a binding early decision plan and places your application in the regular pile, you are no longer bound to attend if admitted. Therefore, you are able to shift gears and make a second early decision choice.
One thing to remember, however, is that you will most likely hear back from your ED2 school well before you will hear from any of your regular decision schools -- and if you are accepted, you have committed to withdrawing all other applications. So you will never know if you would have gotten into that ED1 school. If you're OK with that, go for it!!