We have studied this issue since yours truly was in college. While the corporate media has always been leftist and has been very willing to lie about Republicans such as Ronald Reagan and Sarah Palin, the first example of creating a fake news site as a partisan tactic was Mitt Romney. Since that time the left has picked up that tactic and ran with it.
The video is disabled for playing on websites so be sure to follow the link. – https://www.youtube.com/watch?v=oa7QvcKYGZA