As you can see I just wrapped up Season 1 of my rewatch last night. My first time watching it was in the Summer of 2012. I was just a 21 year old College kid who didn't know jackshit about jackshit. So much so that I've lived the last 8 years with the belief that Junior was the bad guy. He ordered the hit on his own nephew! It had to be him, right?
29 year old Eddie isn't so sure anymore. While there is certainly an argument for Junior since he did make the move, it's very clear to me that the old sour Livia was the one who planted it all in Juniors head. I threw Mikey Palmice in the poll as well because he also planted some stuff, but nowhere near to the degree that Livia did. She told Junior about the psychiatrist. She told him about the capos' meeting Tony at Green Grove. She knew exactly what she was doing so in my eyes she takes the lion-share of the blame.
Yes, Junior & Mikey should get some, and I can even argue Tony deserves a small, small percentage due to him giving his Uncle shit about muff diving, but the final answer here now and forever is Livia Soprano.
Thank you for your time.
P.S. - Carl just said that the true bad guy is actually Jackie Aprile's cancer and that put my brain into a pretzel.