I like that you researched the authors of the article, since their experience and work can affect the legitimacy of writing and the presence of possible biases. It was also smart to use the media bias rating system, especially one that is a public benefit corporation, making its reporting more balanced. I think it would be best in proving this claim if you could find the original source of the data, such as financial records of the campaigns, rather than relying on multiple news sources, no matter how credible they may be.