(This question is inspired by current events, but I'm changing details to avoid the complications of reality!)
In the midst of a reelection campaign, Senator Johnson shot his wife's poorly behaved puppy, without her knowledge or consent. A tabloid reporter documented the event. A wealthy friend of Senator Johnson's pays the tabloid to bury the (ahem) story.
If the friend's gift is conceived as having a political intent, it might constitute an illegal campaign contribution (might... I don't know all of those circumstances). But then it could just as easily be construed as a friend helping Senator Johnson to keep the puppy affair from his wife.
In this kind of situation, does the accused get a presumption of having the non-illegal intent? If so, how would it be possible to ever prosecute these kinds of transactions, since many things that might be politically damaging could also be construed as being personally humiliating?