If your state hasn't voted yet in the primary elections, as California has not, and you are a Decline to State voter, you might still have time to register as a Republican for the primary to support Trump.

I am a Decline to State voter and I have already received notice to ask for a primary ballot selecting a political party that allows Decline to State voters to vote in their primaries. This does not include the Republicans, they do not allow Decline to State voters to vote in their primaries. So here is what I am going to do. I am going to register before the deadline (here in CA) as a Republican. When the primaries are over, I will register again as a Decline to State voter. This is how you change political parties here in CA, you just send in another voter registration form with the new political party or Decline to State checked off. I want to give Trump whatever edge I can contribute.

I'm guessing all the Cruz supporters and Trump haters who are self described conservatives are already registered Republicans.