I originally posted this message at another forum, but go no response and it's been a day since I posted it. I thought it was odd because this should be an easy solution:
I need to test critera based on three subjects:

Is the user logged in? If not, skip all code.
Does the User's "Vote" model contain something other than nil? If so, continue.
Does the User's Vote correspond to the current page ID? If so, deny another vote. If not, save the vote.
This would work if I didn't run into one small problem in the controller: I have to check to see if Vote is nil before trying to see if the User's vote corresponds to the page ID. This, in turn, means that I can only use "IF this AND that" for two values- "this" and "that". This is bad, since I have three conditions to check.

Is there a way to check for all three conditions or not? I also tried nesting the IF statements, but to no avail.

Perhaps my syntax is wrong?