Trump is accused of being personally involved in a fraudulent scheme.
Obama's campaign didn’t timely report what generally were a whole bunch of small contributions. Big difference in personal involvement.
Link: https://www.washingtonpost.com/news/politics/wp/2018/08/22/trumps-comparison-of-the-cohen-allegations-to-obama-is-entirely-wrong/?utm_term=.5775b5e8e29c