Coincidentally, today Trump's personal lawyer Michael Cohen pled guilty (without a trial) to several counts of tax fraud and bank fraud, plus what he claims was an illegal payoff of Stormy Daniels "at the direction of the candidate." It is this last plea that becomes problematic for Trump.
Law prof Jonathan Turley, speaking on the Bret Baier Special Report on Fox News, said whether or not doing so constitutes an illegal campaign contribution is not a settled question. Fox legal analyst Shannon Bream concurred.
For a man to pay a woman to remain silent about an affair is not, per se, illegal. When that man is a candidate, does that otherwise legal payment become a campaign contribution which, if sizable, exceeds the maximum someone can lawfully donate?
If the payment was made with Trump's money, I can't see that it is a campaign contribution as there is no limit on the amount of personal money one can spend running for office. What makes this situation cloudy is that apparently Cohen fronted Trump the payoff money and was repaid later.
Until repaid, did this loan constitute an illegally large campaign contribution? Mueller will argue it did, Trump will argue it did not. To try for a reduced sentence recommendation, Cohen has agreed with Mueller's interpretation. Admitted felons of low character like Cohen do not make especially credible witnesses.
Perhaps Mueller aims to assemble abundant evidence of Trump’s low character as ammunition for an impeachment effort should Democrats retake the House majority in November. Paying off bimbos with whom one had thinly disguised hooker/client interactions is not a hallmark of outstanding character. Employing a sleazy shyster like Cohen suggests the client holds similar scofflaw attitudes, also not a good look.
We live in interesting times. I can imagine a future in which we say of the Trump presidency, as we have said of the Nixon presidency, that he accomplished some very good things but was brought down by his character flaws. That, by the way, is not a prediction, merely a possible scenario.