Hahaha... right, because when you register to vote they always ask your party preference.
In Michigan it is not allowed. if you want to pick a certain type voter you set up booths in the neighborhood you think has the most of them. But you still get both. You cannot refuse anyone. if they sign it Donald duck, you turn it in The election commision will take care of it from there.You make no decisions. Just answer questions if they want to know the qualifications.