When the Clinton Foundation hired a hit man to whack Seth Rich and silence him in order to prevent an embarrassment to the Hillary campaign; was that an illegal campaign contribution?
Unfortunately it's not prosecutable until such a time a the hitman is identified as a hitman and not a random murderer, and such a time as the trail of financing is established between the Clinton Foundation and the hit man, and other possibilities are eliminated such as payments between the FSB or other interested party and the hit man. The Dems don't have to build real cases when their goal is a timely political smear for an election rather than a rock solid prosecution. Assassination by lawfare is going to be the Democrat go-to method of winning as long as Democrats do not incur any penalties for their behavior... and the Democrat willingness to break the law and destroy people is itself a deterrent to any but the fiercest of prosecutors who have nothing to lose. Name even one such prosecutor. Is there such a person in America? It is like the courts in South America where judges had to be hidden behind masks or else the narcoterrorists would eliminate them... even then they were not safe from betrayal from within the system. Anyone who dares to go after a powerful democrat in our system has no such anonymity and can only do so if he has the world's brassiest balls and no family or friends or even neighbors for the Democrats to go after.